diff --git a/README.md b/README.md
index 24e1f47..229cfcd 100644
--- a/README.md
+++ b/README.md
@@ -99,9 +99,18 @@ status: pending
 assignee: bob
 depends_on:
   - oauth-flow
+repo: webapp
+agent: codex
+model: gpt-5.5
+reasoning_effort: high
 branch: feat/payment-integration
 ```
 
+`repo`/`repos` routes work to the right repository in multi-repo projects. `agent` routes a spec
+to a specific installed agent (`claude-code`, `codex`, or `gemini`); if omitted, dispatch uses
+`agent.type` from `sail.yaml`. `model` and `reasoning_effort` tune agents that support those
+controls; unsupported combinations fail fast.
+
 ### Lifecycle
 
 ```
@@ -253,6 +262,7 @@ agent:
   type: claude-code
   install:
     - claude-code
+    - codex
     - gemini
   security_audit:
     enabled: true
@@ -261,7 +271,10 @@ agent:
     enabled: true
 ```
 
-Claude codes. Gemini reviews. Or the same agent does both with fresh context. The hooks fire at spec completion, not session stop — so reviews always see complete, coherent work.
+Claude, Codex, or Gemini can execute a spec. Set `agent: codex` in `spec.yaml` to override the
+project default for that unit of work. For Codex, `model` and `reasoning_effort` map to
+`codex exec --model ... --config model_reasoning_effort=...`. The hooks fire at spec completion,
+not session stop — so reviews always see complete, coherent work.
 
 ## Example `sail.yaml`
 
diff --git a/sail-core/src/main/java/ai/singlr/sail/config/Spec.java b/sail-core/src/main/java/ai/singlr/sail/config/Spec.java
index df859fe..d0ed4bd 100644
--- a/sail-core/src/main/java/ai/singlr/sail/config/Spec.java
+++ b/sail-core/src/main/java/ai/singlr/sail/config/Spec.java
@@ -5,11 +5,14 @@
 
 package ai.singlr.sail.config;
 
+import ai.singlr.sail.engine.AgentCli;
 import ai.singlr.sail.engine.NameValidator;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
+import java.util.Set;
+import java.util.regex.Pattern;
 
 /**
  * A single spec representing one unit of work. Each spec lives in its own directory inside the
@@ -22,6 +25,9 @@
  * @param assignee engineer responsible (nullable, matches git identity)
  * @param dependsOn IDs of specs that must be done first
  * @param repos repository paths this spec should branch and work in
+ * @param agent agent CLI this spec should run with (nullable)
+ * @param model model this spec should run with (nullable)
+ * @param reasoningEffort model reasoning effort for this spec (nullable)
  * @param branch git branch for this spec's work (nullable)
  */
 public record Spec(
@@ -31,8 +37,15 @@ public record Spec(
     String assignee,
     List<String> dependsOn,
     List<String> repos,
+    String agent,
+    String model,
+    String reasoningEffort,
     String branch) {
 
+  private static final Pattern MODEL_PATTERN = Pattern.compile("[A-Za-z0-9._:/-]+");
+  private static final Set<String> REASONING_EFFORTS =
+      Set.of("none", "low", "medium", "high", "xhigh");
+
   public Spec(
       String id,
       String title,
@@ -40,7 +53,30 @@ public Spec(
       String assignee,
       List<String> dependsOn,
       String branch) {
-    this(id, title, status, assignee, dependsOn, List.of(), branch);
+    this(id, title, status, assignee, dependsOn, List.of(), null, null, null, branch);
+  }
+
+  public Spec(
+      String id,
+      String title,
+      String status,
+      String assignee,
+      List<String> dependsOn,
+      List<String> repos,
+      String branch) {
+    this(id, title, status, assignee, dependsOn, repos, null, null, null, branch);
+  }
+
+  public Spec(
+      String id,
+      String title,
+      String status,
+      String assignee,
+      List<String> dependsOn,
+      List<String> repos,
+      String agent,
+      String branch) {
+    this(id, title, status, assignee, dependsOn, repos, agent, null, null, branch);
   }
 
   @SuppressWarnings("unchecked")
@@ -55,6 +91,9 @@ public static Spec fromMap(Map<String, Object> map) {
     var assignee = (String) map.get("assignee");
     var dependsOn = (List<String>) map.get("depends_on");
     var repos = reposFromMap(map);
+    var agent = validatedAgent((String) map.get("agent"));
+    var model = validatedModel((String) map.get("model"));
+    var reasoningEffort = validatedReasoningEffort((String) map.get("reasoning_effort"));
     var branch = (String) map.get("branch");
     return new Spec(
         id,
@@ -63,6 +102,9 @@ public static Spec fromMap(Map<String, Object> map) {
         assignee,
         dependsOn != null ? List.copyOf(dependsOn) : List.of(),
         repos,
+        agent,
+        model,
+        reasoningEffort,
         branch);
   }
 
@@ -84,6 +126,15 @@ public Map<String, Object> toMap() {
     } else if (!repos.isEmpty()) {
       map.put("repos", repos);
     }
+    if (agent != null) {
+      map.put("agent", agent);
+    }
+    if (model != null) {
+      map.put("model", model);
+    }
+    if (reasoningEffort != null) {
+      map.put("reasoning_effort", reasoningEffort);
+    }
     if (branch != null) {
       map.put("branch", branch);
     }
@@ -109,4 +160,37 @@ private static List<String> validatedRepos(List<String> repos) {
     repos.forEach(repo -> NameValidator.requireSafePath(repo, "spec.repo"));
     return List.copyOf(repos);
   }
+
+  private static String validatedAgent(String agent) {
+    if (agent == null || agent.isBlank()) {
+      return null;
+    }
+    AgentCli.fromYamlName(agent);
+    return agent;
+  }
+
+  private static String validatedModel(String model) {
+    if (model == null || model.isBlank()) {
+      return null;
+    }
+    if (!MODEL_PATTERN.matcher(model).matches()) {
+      throw new IllegalArgumentException(
+          "Invalid spec.model: '" + model + "'. Use a model id without spaces or shell syntax.");
+    }
+    return model;
+  }
+
+  private static String validatedReasoningEffort(String reasoningEffort) {
+    if (reasoningEffort == null || reasoningEffort.isBlank()) {
+      return null;
+    }
+    if (!REASONING_EFFORTS.contains(reasoningEffort)) {
+      throw new IllegalArgumentException(
+          "Invalid spec.reasoning_effort: '"
+              + reasoningEffort
+              + "'. Must be one of: "
+              + String.join(", ", REASONING_EFFORTS));
+    }
+    return reasoningEffort;
+  }
 }
diff --git a/sail-core/src/main/java/ai/singlr/sail/config/SpecDirectory.java b/sail-core/src/main/java/ai/singlr/sail/config/SpecDirectory.java
index 1534212..0b5b214 100644
--- a/sail-core/src/main/java/ai/singlr/sail/config/SpecDirectory.java
+++ b/sail-core/src/main/java/ai/singlr/sail/config/SpecDirectory.java
@@ -107,6 +107,9 @@ public static List<Spec> updateStatus(List<Spec> specs, String specId, String ne
                         spec.assignee(),
                         spec.dependsOn(),
                         spec.repos(),
+                        spec.agent(),
+                        spec.model(),
+                        spec.reasoningEffort(),
                         spec.branch())
                     : spec)
         .toList();
diff --git a/sail-core/src/main/java/ai/singlr/sail/engine/AgentCli.java b/sail-core/src/main/java/ai/singlr/sail/engine/AgentCli.java
index 02ad7d1..3840064 100644
--- a/sail-core/src/main/java/ai/singlr/sail/engine/AgentCli.java
+++ b/sail-core/src/main/java/ai/singlr/sail/engine/AgentCli.java
@@ -95,17 +95,24 @@ public String displayName() {
    * @param fullPermissions whether to auto-approve all actions
    */
   public String headlessCommand(String taskFile, boolean fullPermissions) {
+    return headlessCommand(taskFile, fullPermissions, null, null);
+  }
+
+  public String headlessCommand(
+      String taskFile, boolean fullPermissions, String model, String reasoningEffort) {
     var task = "\"$(cat " + taskFile + ")\"";
     return switch (this) {
       case CLAUDE_CODE -> {
+        requireNoModelOptions(model, reasoningEffort);
         var perm = fullPermissions ? " --dangerously-skip-permissions" : "";
         yield binaryName + " --print" + perm + " -p " + task;
       }
       case CODEX -> {
         var perm = fullPermissions ? " --full-auto" : "";
-        yield binaryName + " exec" + perm + " " + task;
+        yield binaryName + " exec" + perm + codexModelOptions(model, reasoningEffort) + " " + task;
       }
       case GEMINI -> {
+        requireNoModelOptions(model, reasoningEffort);
         var perm = fullPermissions ? " --yolo" : "";
         yield binaryName + perm + " -p " + task;
       }
@@ -143,4 +150,22 @@ public static AgentCli fromYamlName(String name) {
             + "'. Known agents: claude-code, codex, gemini."
             + "\n  Check the 'install' list in your sail.yaml agent section.");
   }
+
+  private static String codexModelOptions(String model, String reasoningEffort) {
+    var options = new StringBuilder();
+    if (model != null) {
+      options.append(" --model ").append(model);
+    }
+    if (reasoningEffort != null) {
+      options.append(" --config model_reasoning_effort='\"").append(reasoningEffort).append("\"'");
+    }
+    return options.toString();
+  }
+
+  private void requireNoModelOptions(String model, String reasoningEffort) {
+    if (model != null || reasoningEffort != null) {
+      throw new IllegalArgumentException(
+          yamlName + " does not support spec-level model or reasoning_effort options yet.");
+    }
+  }
 }
diff --git a/sail-core/src/main/java/ai/singlr/sail/gen/AgentContextGenerator.java b/sail-core/src/main/java/ai/singlr/sail/gen/AgentContextGenerator.java
index bfa017b..633e2cc 100644
--- a/sail-core/src/main/java/ai/singlr/sail/gen/AgentContextGenerator.java
+++ b/sail-core/src/main/java/ai/singlr/sail/gen/AgentContextGenerator.java
@@ -455,7 +455,7 @@ private static void appendSpecSection(StringBuilder sb, SailYaml config) {
         ```
         %s/
         ├── oauth-flow/
-        │   ├── spec.yaml        # Metadata: id, title, status, assignee, depends_on, repo/repos, branch
+        │   ├── spec.yaml        # Metadata: id, title, status, assignee, depends_on, repo/repos, agent, branch
         │   ├── spec.md          # Detailed specification
         │   └── plan.md          # Optional implementation plan
         └── search-api/
@@ -474,6 +474,9 @@ private static void appendSpecSection(StringBuilder sb, SailYaml config) {
         assignee: claude-code
         depends_on: []
         repo: app
+        agent: codex
+        model: gpt-5.5
+        reasoning_effort: high
         branch: feat/oauth-flow
         ```
 
@@ -481,6 +484,14 @@ private static void appendSpecSection(StringBuilder sb, SailYaml config) {
         work. The values must match `repos[].path` in `sail.yaml`. If a multi-repository
         project omits repo targeting, `sail spec dispatch` will not auto-create a branch.
 
+        Use `agent: codex`, `agent: claude-code`, or `agent: gemini` when a spec should run on
+        a specific installed agent. If omitted, `sail spec dispatch` uses `agent.type` from
+        `sail.yaml`.
+
+        Use `model` and `reasoning_effort` when the selected agent supports those controls. Codex
+        supports both; unsupported combinations fail during dispatch instead of silently falling
+        back.
+
         ### Status Lifecycle
         `pending` → `in_progress` → `review` → `done`
         Spec status is managed by `sail`, not by you. Do not modify spec status directly during autonomous execution.
diff --git a/sail-core/src/main/java/ai/singlr/sail/gen/SpecSkillGenerator.java b/sail-core/src/main/java/ai/singlr/sail/gen/SpecSkillGenerator.java
index d9a502b..4dacc02 100644
--- a/sail-core/src/main/java/ai/singlr/sail/gen/SpecSkillGenerator.java
+++ b/sail-core/src/main/java/ai/singlr/sail/gen/SpecSkillGenerator.java
@@ -243,6 +243,9 @@ private static String createInstructions(String specsDir) {
            status: pending
            depends_on: []
            repo: <repo-path>
+           agent: <claude-code|codex|gemini>
+           model: <model-id>
+           reasoning_effort: <none|low|medium|high|xhigh>
            ```
         4. Write `%1$s/<id>/spec.md` using the spec template
         5. Confirm: "Created spec `<id>` — fill in the details in `%1$s/<id>/spec.md`"
@@ -256,6 +259,14 @@ private static String createInstructions(String specsDir) {
         Ask which repository the spec targets when the project has multiple repos. Use \
         `repo: <path>` for one repo and `repos: [repo-a, repo-b]` for cross-repo work. \
         Values must match `repos[].path` in `sail.yaml`.
+
+        Ask which agent should execute the spec when the project has multiple installed agents. \
+        Use `agent: codex`, `agent: claude-code`, or `agent: gemini`. If omitted, Sail uses \
+        `agent.type` from `sail.yaml`.
+
+        Ask which model and reasoning effort to use when the selected agent supports them. \
+        For Codex, use `model: gpt-5.5` and `reasoning_effort: high` when the engineer wants \
+        GPT-5.5 with high reasoning.
         """
         .formatted(specsDir);
   }
@@ -308,6 +319,9 @@ private static String coreReference(String specsDir) {
         assignee: claude-code
         depends_on: []
         repo: app
+        agent: codex
+        model: gpt-5.5
+        reasoning_effort: high
         branch: feat/oauth-flow
         ```
 
@@ -331,12 +345,21 @@ private static String coreReference(String specsDir) {
         - **depends_on** (optional): list of spec ids that must be done first
         - **repo** (optional): single target repository path from `sail.yaml` `repos[].path`
         - **repos** (optional): list of target repository paths for cross-repo work
+        - **agent** (optional): agent CLI for this spec (`claude-code`, `codex`, or `gemini`)
+        - **model** (optional): model id for agents that support model selection
+        - **reasoning_effort** (optional): `none`, `low`, `medium`, `high`, or `xhigh`
         - **branch** (optional): git branch name for this spec's work
 
         In multi-repo projects, always include `repo` or `repos` before dispatch so Sail can \
         create the branch in the right repository. If omitted, dispatch only auto-branches when \
         the project has exactly one configured repo.
 
+        In multi-agent projects, include `agent` when a spec should run on a non-default agent. \
+        If omitted, dispatch uses `agent.type` from `sail.yaml`.
+
+        Include `model` and `reasoning_effort` only for agents that support them. Sail passes \
+        these to Codex and rejects unsupported combinations for other agents.
+
         ### Directory Structure
         ```
         %s/
diff --git a/sail-core/src/test/java/ai/singlr/sail/config/SpecTest.java b/sail-core/src/test/java/ai/singlr/sail/config/SpecTest.java
index b8a6d4b..3ba8e6d 100644
--- a/sail-core/src/test/java/ai/singlr/sail/config/SpecTest.java
+++ b/sail-core/src/test/java/ai/singlr/sail/config/SpecTest.java
@@ -105,6 +105,42 @@ void toMapContainsAllFields() {
     assertEquals("feat/auth", map.get("branch"));
   }
 
+  @Test
+  void parsesAgent() {
+    var spec = Spec.fromMap(Map.of("id", "auth", "agent", "codex"));
+
+    assertEquals("codex", spec.agent());
+  }
+
+  @Test
+  void rejectsUnknownAgent() {
+    assertThrows(
+        IllegalArgumentException.class,
+        () -> Spec.fromMap(Map.of("id", "auth", "agent", "unknown-agent")));
+  }
+
+  @Test
+  void parsesModelAndReasoningEffort() {
+    var spec = Spec.fromMap(Map.of("id", "auth", "model", "gpt-5.5", "reasoning_effort", "high"));
+
+    assertEquals("gpt-5.5", spec.model());
+    assertEquals("high", spec.reasoningEffort());
+  }
+
+  @Test
+  void rejectsUnsafeModel() {
+    assertThrows(
+        IllegalArgumentException.class,
+        () -> Spec.fromMap(Map.of("id", "auth", "model", "gpt-5.5; rm -rf /")));
+  }
+
+  @Test
+  void rejectsUnknownReasoningEffort() {
+    assertThrows(
+        IllegalArgumentException.class,
+        () -> Spec.fromMap(Map.of("id", "auth", "reasoning_effort", "huge")));
+  }
+
   @Test
   void toMapWritesSingleRepoAsRepo() {
     var spec =
@@ -164,6 +200,9 @@ void roundTrips() {
     assertEquals(spec.assignee(), parsed.assignee());
     assertEquals(spec.dependsOn(), parsed.dependsOn());
     assertEquals(spec.repos(), parsed.repos());
+    assertEquals(spec.agent(), parsed.agent());
+    assertEquals(spec.model(), parsed.model());
+    assertEquals(spec.reasoningEffort(), parsed.reasoningEffort());
     assertEquals(spec.branch(), parsed.branch());
   }
 
diff --git a/sail-harness/src/main/java/ai/singlr/sail/engine/AgentSession.java b/sail-harness/src/main/java/ai/singlr/sail/engine/AgentSession.java
index 66ada73..7aec718 100644
--- a/sail-harness/src/main/java/ai/singlr/sail/engine/AgentSession.java
+++ b/sail-harness/src/main/java/ai/singlr/sail/engine/AgentSession.java
@@ -157,8 +157,20 @@ public static List<String> buildBackgroundLaunchCommand(
       String workDir,
       boolean fullPermissions,
       AgentCli agentCli) {
+    return buildBackgroundLaunchCommand(
+        containerName, sshUser, workDir, fullPermissions, agentCli, null, null);
+  }
+
+  public static List<String> buildBackgroundLaunchCommand(
+      String containerName,
+      String sshUser,
+      String workDir,
+      boolean fullPermissions,
+      AgentCli agentCli,
+      String model,
+      String reasoningEffort) {
     var cli = Objects.requireNonNullElse(agentCli, AgentCli.CLAUDE_CODE);
-    var agentCmd = cli.headlessCommand(TASK_FILE, fullPermissions);
+    var agentCmd = cli.headlessCommand(TASK_FILE, fullPermissions, model, reasoningEffort);
     var script =
         "mkdir -p \"$1\" && cd \"$2\" && bash -l -c \"$3\" > \"$4\" 2>&1 & echo $! > \"$5\"";
     return ContainerExec.asDevUser(
@@ -178,8 +190,20 @@ public static List<String> buildForegroundTaskCommand(
       String workDir,
       boolean fullPermissions,
       AgentCli agentCli) {
+    return buildForegroundTaskCommand(
+        containerName, sshUser, workDir, fullPermissions, agentCli, null, null);
+  }
+
+  public static List<String> buildForegroundTaskCommand(
+      String containerName,
+      String sshUser,
+      String workDir,
+      boolean fullPermissions,
+      AgentCli agentCli,
+      String model,
+      String reasoningEffort) {
     var cli = Objects.requireNonNullElse(agentCli, AgentCli.CLAUDE_CODE);
-    var agentCmd = cli.headlessCommand(TASK_FILE, fullPermissions);
+    var agentCmd = cli.headlessCommand(TASK_FILE, fullPermissions, model, reasoningEffort);
     var script = "cd \"$1\" && bash -l -c \"$2\"";
     return ContainerExec.asDevUser(
         containerName, List.of("bash", "-l", "-c", script, "bash", workDir, agentCmd));
diff --git a/sail-harness/src/test/java/ai/singlr/sail/engine/AgentSessionTest.java b/sail-harness/src/test/java/ai/singlr/sail/engine/AgentSessionTest.java
index e5efe26..a97b84b 100644
--- a/sail-harness/src/test/java/ai/singlr/sail/engine/AgentSessionTest.java
+++ b/sail-harness/src/test/java/ai/singlr/sail/engine/AgentSessionTest.java
@@ -202,6 +202,32 @@ void buildBackgroundLaunchCommandCodexFullAuto() {
     assertTrue(joined.contains("codex exec --full-auto"));
   }
 
+  @Test
+  void buildBackgroundLaunchCommandCodexModelOptions() {
+    var cmd =
+        AgentSession.buildBackgroundLaunchCommand(
+            "acme", "dev", "/home/dev/workspace", true, AgentCli.CODEX, "gpt-5.5", "high");
+
+    var joined = String.join(" ", cmd);
+    assertTrue(joined.contains("codex exec --full-auto --model gpt-5.5"));
+    assertTrue(joined.contains("model_reasoning_effort='\"high\"'"));
+  }
+
+  @Test
+  void buildBackgroundLaunchCommandRejectsUnsupportedModelOptions() {
+    assertThrows(
+        IllegalArgumentException.class,
+        () ->
+            AgentSession.buildBackgroundLaunchCommand(
+                "acme",
+                "dev",
+                "/home/dev/workspace",
+                true,
+                AgentCli.CLAUDE_CODE,
+                "gpt-5.5",
+                "high"));
+  }
+
   @Test
   void buildBackgroundLaunchCommandGeminiUsesYolo() {
     var cmd =
diff --git a/sail-infra/src/main/java/ai/singlr/sail/api/ApiModels.java b/sail-infra/src/main/java/ai/singlr/sail/api/ApiModels.java
index 85032fa..36b01d5 100644
--- a/sail-infra/src/main/java/ai/singlr/sail/api/ApiModels.java
+++ b/sail-infra/src/main/java/ai/singlr/sail/api/ApiModels.java
@@ -102,6 +102,9 @@ record SpecView(
     String assignee,
     List<String> dependsOn,
     List<String> repos,
+    String agent,
+    String model,
+    String reasoningEffort,
     String branch,
     boolean ready,
     boolean blocked,
@@ -114,7 +117,14 @@ record SpecView(
 }
 
 record DispatchedSpecView(
-    String id, String title, String status, List<String> repos, String branch) {
+    String id,
+    String title,
+    String status,
+    List<String> repos,
+    String agent,
+    String model,
+    String reasoningEffort,
+    String branch) {
   public DispatchedSpecView {
     repos = repos == null ? List.of() : List.copyOf(repos);
   }
diff --git a/sail-infra/src/main/java/ai/singlr/sail/api/SailApiOperations.java b/sail-infra/src/main/java/ai/singlr/sail/api/SailApiOperations.java
index ab6d86c..0a8228e 100644
--- a/sail-infra/src/main/java/ai/singlr/sail/api/SailApiOperations.java
+++ b/sail-infra/src/main/java/ai/singlr/sail/api/SailApiOperations.java
@@ -205,12 +205,13 @@ private DispatchResponse dispatchValue(String project, DispatchRequest request)
     updateStatus(workspace, nextSpec.id(), "in_progress");
     var specBody = Objects.requireNonNullElse(readSpecBody(workspace, nextSpec.id()), "");
     var task = buildTaskPrompt(taskSpec, specBody.isBlank() ? nextSpec.title() : specBody);
+    var agentType = taskSpec.agent() != null ? taskSpec.agent() : loaded.config().agent().type();
     var branch = branchName(loaded.config(), nextSpec);
     var snapshot = createSnapshotIfNeeded(project, loaded.config());
     var branchCreated = createBranchIfNeeded(project, loaded.config(), targetRepos, branch);
 
     if (!request.dryRun()) {
-      launchAgent(project, loaded.config(), task, branch, request.mode());
+      launchAgent(project, loaded.config(), task, branch, request.mode(), taskSpec, agentType);
     }
 
     var status = request.dryRun() ? null : querySession(agentSession, project);
@@ -219,7 +220,7 @@ private DispatchResponse dispatchValue(String project, DispatchRequest request)
         true,
         null,
         dispatchedSpecView(taskSpec, branch),
-        agentStatusView(loaded.config(), request.mode(), status),
+        agentStatusView(agentType, request.mode(), status),
         snapshot,
         branchCreated);
   }
@@ -404,6 +405,9 @@ private static SpecView specView(List<Spec> specs, Spec spec) {
         spec.assignee(),
         spec.dependsOn(),
         spec.repos(),
+        spec.agent(),
+        spec.model(),
+        spec.reasoningEffort(),
         spec.branch(),
         SpecDirectory.isReady(specs, spec),
         SpecDirectory.isBlocked(specs, spec),
@@ -445,6 +449,9 @@ private static DispatchedSpecView dispatchedSpecView(Spec spec, String branch) {
         spec.title(),
         "in_progress",
         spec.repos(),
+        spec.agent(),
+        spec.model(),
+        spec.reasoningEffort(),
         branch != null && !branch.isBlank() ? branch : null);
   }
 
@@ -456,6 +463,9 @@ private static Spec withTargetRepos(Spec spec, List<SailYaml.Repo> targetRepos)
         spec.assignee(),
         spec.dependsOn(),
         targetRepos.stream().map(SailYaml.Repo::path).toList(),
+        spec.agent(),
+        spec.model(),
+        spec.reasoningEffort(),
         spec.branch());
   }
 
@@ -468,12 +478,21 @@ private static String buildTaskPrompt(Spec spec, String description) {
                 + ": "
                 + String.join(", ", spec.repos())
                 + "\n";
+    var targetAgent = spec.agent() == null ? "" : "\nTarget agent: " + spec.agent() + "\n";
+    var targetModel = spec.model() == null ? "" : "\nTarget model: " + spec.model() + "\n";
+    var targetReasoning =
+        spec.reasoningEffort() == null
+            ? ""
+            : "\nTarget reasoning effort: " + spec.reasoningEffort() + "\n";
     return "Your current spec: \""
         + spec.title()
         + "\" (id: "
         + spec.id()
         + ")."
         + targetRepos
+        + targetAgent
+        + targetModel
+        + targetReasoning
         + "\n"
         + description;
   }
@@ -531,20 +550,38 @@ private boolean createBranchIfNeeded(
   }
 
   private void launchAgent(
-      String project, SailYaml config, String task, String branch, String mode) {
+      String project,
+      SailYaml config,
+      String task,
+      String branch,
+      String mode,
+      Spec spec,
+      String agentType) {
     try {
       var session = new AgentSession(shell);
       session.ensureDirectory(project);
       session.writeTaskFile(project, task);
       session.writeSession(project, task, Objects.requireNonNullElse(branch, ""));
-      var agentCli = AgentCli.fromYamlName(config.agent().type());
+      var agentCli = AgentCli.fromYamlName(agentType);
       var workDir = "/home/" + config.sshUser() + "/workspace";
       var command =
           mode.equals("background")
               ? AgentSession.buildBackgroundLaunchCommand(
-                  project, config.sshUser(), workDir, true, agentCli)
+                  project,
+                  config.sshUser(),
+                  workDir,
+                  true,
+                  agentCli,
+                  spec.model(),
+                  spec.reasoningEffort())
               : AgentSession.buildForegroundTaskCommand(
-                  project, config.sshUser(), workDir, true, agentCli);
+                  project,
+                  config.sshUser(),
+                  workDir,
+                  true,
+                  agentCli,
+                  spec.model(),
+                  spec.reasoningEffort());
       var result = exec(command);
       if (!result.ok()) {
         throw new ApiException(ErrorCode.AGENT_LAUNCH_FAILED, "Failed to launch agent.");
@@ -608,9 +645,9 @@ private static AgentConfigView agentConfigView(SailYaml config) {
   }
 
   private static AgentStatusView agentStatusView(
-      SailYaml config, String mode, AgentSession.SessionInfo info) {
+      String agentType, String mode, AgentSession.SessionInfo info) {
     return new AgentStatusView(
-        config.agent() != null ? config.agent().type() : "",
+        agentType,
         mode,
         info != null && info.running(),
         info != null ? info.pid() : null,
diff --git a/sail-infra/src/main/java/ai/singlr/sail/commands/DispatchCommand.java b/sail-infra/src/main/java/ai/singlr/sail/commands/DispatchCommand.java
index 09545b9..7eec436 100644
--- a/sail-infra/src/main/java/ai/singlr/sail/commands/DispatchCommand.java
+++ b/sail-infra/src/main/java/ai/singlr/sail/commands/DispatchCommand.java
@@ -172,7 +172,7 @@ private void execute() throws Exception {
       System.out.println();
     }
 
-    var agentType = config.agent().type();
+    var agentType = taskSpec.agent() != null ? taskSpec.agent() : config.agent().type();
     var agentCli = AgentCli.fromYamlName(agentType);
     var workDir = "/home/" + sshUser + "/workspace";
     var fullPermissions = true;
@@ -242,7 +242,13 @@ private void execute() throws Exception {
     if (background) {
       var sshCmd =
           AgentSession.buildBackgroundLaunchCommand(
-              name, sshUser, workDir, fullPermissions, agentCli);
+              name,
+              sshUser,
+              workDir,
+              fullPermissions,
+              agentCli,
+              taskSpec.model(),
+              taskSpec.reasoningEffort());
       if (!json) {
         System.out.println(Ansi.AUTO.string("  @|bold Launching agent in background...|@"));
         System.out.println(Ansi.AUTO.string("  @|faint " + String.join(" ", sshCmd) + "|@"));
@@ -261,7 +267,13 @@ private void execute() throws Exception {
     } else {
       var sshCmd =
           AgentSession.buildForegroundTaskCommand(
-              name, sshUser, workDir, fullPermissions, agentCli);
+              name,
+              sshUser,
+              workDir,
+              fullPermissions,
+              agentCli,
+              taskSpec.model(),
+              taskSpec.reasoningEffort());
       if (!json) {
         System.out.println(Ansi.AUTO.string("  @|bold Launching agent with spec...|@"));
         System.out.println(Ansi.AUTO.string("  @|faint " + String.join(" ", sshCmd) + "|@"));
@@ -299,12 +311,21 @@ static String buildTaskPrompt(Spec spec, String description, String specsDir) {
                 + ": "
                 + String.join(", ", spec.repos())
                 + "\n";
+    var targetAgent = spec.agent() == null ? "" : "\nTarget agent: " + spec.agent() + "\n";
+    var targetModel = spec.model() == null ? "" : "\nTarget model: " + spec.model() + "\n";
+    var targetReasoning =
+        spec.reasoningEffort() == null
+            ? ""
+            : "\nTarget reasoning effort: " + spec.reasoningEffort() + "\n";
     return "Your current spec: \""
         + spec.title()
         + "\" (id: "
         + spec.id()
         + ")."
         + targetRepos
+        + targetAgent
+        + targetModel
+        + targetReasoning
         + "\n"
         + description;
   }
@@ -317,6 +338,9 @@ private static Spec withTargetRepos(Spec spec, List<SailYaml.Repo> targetRepos)
         spec.assignee(),
         spec.dependsOn(),
         targetRepos.stream().map(SailYaml.Repo::path).toList(),
+        spec.agent(),
+        spec.model(),
+        spec.reasoningEffort(),
         spec.branch());
   }
 
diff --git a/sail-infra/src/main/java/ai/singlr/sail/commands/SpecCreateCommand.java b/sail-infra/src/main/java/ai/singlr/sail/commands/SpecCreateCommand.java
index 53159aa..05974f2 100644
--- a/sail-infra/src/main/java/ai/singlr/sail/commands/SpecCreateCommand.java
+++ b/sail-infra/src/main/java/ai/singlr/sail/commands/SpecCreateCommand.java
@@ -10,6 +10,7 @@
 import ai.singlr.sail.config.SpecDirectory;
 import ai.singlr.sail.config.SpecScaffold;
 import ai.singlr.sail.config.YamlUtil;
+import ai.singlr.sail.engine.AgentCli;
 import ai.singlr.sail.engine.Banner;
 import ai.singlr.sail.engine.ContainerManager;
 import ai.singlr.sail.engine.ContainerState;
@@ -53,6 +54,17 @@ public final class SpecCreateCommand implements Runnable {
   @Option(names = "--repo", split = ",", description = "Repository path(s) this spec targets.")
   private List<String> repos;
 
+  @Option(names = "--agent", description = "Agent CLI for this spec (claude-code, codex, gemini).")
+  private String agent;
+
+  @Option(names = "--model", description = "Model id for this spec.")
+  private String model;
+
+  @Option(
+      names = "--reasoning-effort",
+      description = "Reasoning effort for this spec (none, low, medium, high, xhigh).")
+  private String reasoningEffort;
+
   @Option(names = "--depends-on", split = ",", description = "Comma-separated dependency ids.")
   private List<String> dependsOn;
 
@@ -85,6 +97,21 @@ private void execute() throws Exception {
     resolvedDependsOn.forEach(NameValidator::requireValidSpecId);
     var resolvedRepos = repos != null ? List.copyOf(repos) : List.<String>of();
     resolvedRepos.forEach(repo -> NameValidator.requireSafePath(repo, "spec.repo"));
+    if (agent != null) {
+      AgentCli.fromYamlName(agent);
+    }
+    var routingMetadata = new LinkedHashMap<String, Object>();
+    routingMetadata.put("id", resolvedSpecId);
+    if (agent != null) {
+      routingMetadata.put("agent", agent);
+    }
+    if (model != null) {
+      routingMetadata.put("model", model);
+    }
+    if (reasoningEffort != null) {
+      routingMetadata.put("reasoning_effort", reasoningEffort);
+    }
+    var routingProbe = Spec.fromMap(routingMetadata);
 
     var shell = new ShellExecutor(false);
     var mgr = new ContainerManager(shell);
@@ -123,6 +150,9 @@ private void execute() throws Exception {
             assignee,
             resolvedDependsOn,
             resolvedRepos,
+            agent,
+            routingProbe.model(),
+            routingProbe.reasoningEffort(),
             branch);
     workspace.createSpec(spec, SpecScaffold.markdownTemplate(title));
 
diff --git a/sail-infra/src/main/java/ai/singlr/sail/engine/SpecWorkspace.java b/sail-infra/src/main/java/ai/singlr/sail/engine/SpecWorkspace.java
index 6a440f4..9f11fb0 100644
--- a/sail-infra/src/main/java/ai/singlr/sail/engine/SpecWorkspace.java
+++ b/sail-infra/src/main/java/ai/singlr/sail/engine/SpecWorkspace.java
@@ -85,6 +85,9 @@ public Spec updateStatus(String specId, String newStatus)
             spec.assignee(),
             spec.dependsOn(),
             spec.repos(),
+            spec.agent(),
+            spec.model(),
+            spec.reasoningEffort(),
             spec.branch());
     writeMetadata(updated);
     return updated;
diff --git a/sail-infra/src/test/java/ai/singlr/sail/api/ApiRouterTest.java b/sail-infra/src/test/java/ai/singlr/sail/api/ApiRouterTest.java
index 2718763..ae785ac 100644
--- a/sail-infra/src/test/java/ai/singlr/sail/api/ApiRouterTest.java
+++ b/sail-infra/src/test/java/ai/singlr/sail/api/ApiRouterTest.java
@@ -468,6 +468,9 @@ public Result<SpecResponse> spec(String project, String specId) {
                   java.util.List.of(),
                   java.util.List.of(),
                   null,
+                  null,
+                  null,
+                  null,
                   true,
                   false,
                   java.util.List.of()),
@@ -510,7 +513,7 @@ public Result<DispatchResponse> dispatch(String project, DispatchRequest request
               true,
               null,
               new DispatchedSpecView(
-                  request.specId(), "Spec", "in_progress", request.repos(), null),
+                  request.specId(), "Spec", "in_progress", request.repos(), null, null, null, null),
               null,
               "",
               false));
diff --git a/sail-infra/src/test/java/ai/singlr/sail/api/SailApiOperationsTest.java b/sail-infra/src/test/java/ai/singlr/sail/api/SailApiOperationsTest.java
index 4ae0a6b..9fbc607 100644
--- a/sail-infra/src/test/java/ai/singlr/sail/api/SailApiOperationsTest.java
+++ b/sail-infra/src/test/java/ai/singlr/sail/api/SailApiOperationsTest.java
@@ -13,6 +13,7 @@
 import java.nio.file.Path;
 import java.time.Duration;
 import java.time.Instant;
+import java.util.ArrayList;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
@@ -85,6 +86,16 @@ class SailApiOperationsTest {
       branch: feat/custom
       """;
 
+  private static final String AUTH_CODEX_SPEC_YAML =
+      """
+      id: auth
+      title: Add auth
+      status: pending
+      agent: codex
+      model: gpt-5.5
+      reasoning_effort: high
+      """;
+
   private static final String DONE_SPEC_YAML =
       """
       id: done
@@ -564,6 +575,37 @@ void dispatchLaunchesBackgroundAgent() throws Exception {
     assertTrue(get(result, "agent").toString().contains("mode=background"));
   }
 
+  @Test
+  void dispatchUsesSpecAgentWhenPresent() throws Exception {
+    var shell =
+        shell()
+            .on("incus list ^acme$", RUNNING_JSON)
+            .on("cat /home/dev/.sail/agent.pid", new ShellExec.Result(1, "", "missing"))
+            .withCodexSpec()
+            .on("cat /home/dev/workspace/specs/auth/spec.md", "Do auth")
+            .on("mkdir -p /home/dev/workspace/specs", "")
+            .on("printf '%s'", "")
+            .on("mkdir -p /home/dev/.sail", "")
+            .on("codex exec --full-auto --model gpt-5.5", "");
+    var operations = operations(baseYaml(), shell);
+
+    var result = operations.dispatch("acme", request("auth"));
+
+    assertEquals(true, get(result, "dispatched"));
+    assertTrue(get(result, "spec").toString().contains("agent=codex"));
+    assertTrue(get(result, "spec").toString().contains("model=gpt-5.5"));
+    assertTrue(get(result, "spec").toString().contains("reasoning_effort=high"));
+    assertTrue(get(result, "agent").toString().contains("type=codex"));
+    assertTrue(
+        shell.invocations().stream()
+            .anyMatch(
+                command ->
+                    command.contains("codex exec --full-auto --model gpt-5.5")
+                        && command.contains("model_reasoning_effort='\"high\"'")));
+    assertFalse(
+        shell.invocations().stream().anyMatch(command -> command.contains("claude --print")));
+  }
+
   @Test
   void dispatchLaunchesForegroundAgentAndReturnsSessionDetails() throws Exception {
     var operations =
@@ -1103,6 +1145,7 @@ private static FakeShell shell() {
   private static final class FakeShell implements ShellExec {
     private final Map<String, Result> scripts = new LinkedHashMap<>();
     private final Map<String, Exception> failures = new LinkedHashMap<>();
+    private final List<String> invocations = new ArrayList<>();
 
     FakeShell on(String pattern, String stdout) {
       return on(pattern, new Result(0, stdout, ""));
@@ -1134,6 +1177,13 @@ FakeShell withAuthBranchSpec() {
           .on("cat /home/dev/workspace/specs/auth/spec.yaml", AUTH_BRANCH_SPEC_YAML);
     }
 
+    FakeShell withCodexSpec() {
+      return on(
+              "find /home/dev/workspace/specs -mindepth 2 -maxdepth 2 -name spec.yaml -print",
+              "/home/dev/workspace/specs/auth/spec.yaml\n")
+          .on("cat /home/dev/workspace/specs/auth/spec.yaml", AUTH_CODEX_SPEC_YAML);
+    }
+
     FakeShell withDoneSpec() {
       return on(
               "find /home/dev/workspace/specs -mindepth 2 -maxdepth 2 -name spec.yaml -print",
@@ -1144,6 +1194,7 @@ FakeShell withDoneSpec() {
     @Override
     public Result exec(List<String> command) throws IOException {
       var joined = String.join(" ", command);
+      invocations.add(joined);
       for (var entry : failures.entrySet()) {
         if (joined.contains(entry.getKey())) {
           throw (IOException) entry.getValue();
@@ -1166,5 +1217,9 @@ public Result exec(List<String> command, Path workDir, Duration timeout) throws
     public boolean isDryRun() {
       return false;
     }
+
+    List<String> invocations() {
+      return List.copyOf(invocations);
+    }
   }
 }
diff --git a/sail-infra/src/test/java/ai/singlr/sail/commands/DispatchCommandTest.java b/sail-infra/src/test/java/ai/singlr/sail/commands/DispatchCommandTest.java
index 7e05ad0..4348f7a 100644
--- a/sail-infra/src/test/java/ai/singlr/sail/commands/DispatchCommandTest.java
+++ b/sail-infra/src/test/java/ai/singlr/sail/commands/DispatchCommandTest.java
@@ -137,6 +137,29 @@ void buildTaskPromptIncludesFullDescription() {
     assertTrue(prompt.contains("migrations"));
   }
 
+  @Test
+  void buildTaskPromptIncludesTargetAgent() {
+    var spec =
+        new Spec(
+            "ui",
+            "Polish UI",
+            "pending",
+            null,
+            List.of(),
+            List.of("chorus"),
+            "codex",
+            "gpt-5.5",
+            "high",
+            null);
+
+    var prompt = DispatchCommand.buildTaskPrompt(spec, "Details", "specs");
+
+    assertTrue(prompt.contains("Target repo: chorus"));
+    assertTrue(prompt.contains("Target agent: codex"));
+    assertTrue(prompt.contains("Target model: gpt-5.5"));
+    assertTrue(prompt.contains("Target reasoning effort: high"));
+  }
+
   @Test
   void dispatchCommandRegisteredInSing() {
     var cmd = new CommandLine(new Sail());