Bear x-callback-url silently fails section replacement for headers containing / & [ ] |

[vasylenko]

Summary

Bear's /add-text x-callback-url action with mode=replace and header parameter silently fails when the header text contains certain URL-significant characters: /, &, [, ], |. The URL is accepted, open -g exits 0, but Bear does not perform the replacement. No error is surfaced.

This is a Bear app bug in its x-callback-url handler — it appears to interpret these characters at the URL-parsing level before decoding percent-encoded parameter values.

Affected characters

Character	Test Header	Result
/	Topic r/bearapp	❌ Silent no-op
&	Q&A Section	❌ Silent no-op
[ ]	Release [v2.5]	❌ Silent no-op
|	Option A | Option B	❌ Silent no-op

Characters confirmed working

= ? # % + : ; , @ ! ' " — é → — all 15 pass correctly.

Test methodology

Each character was tested with an isolated create → replace → verify → archive cycle using MCP Inspector CLI:

1. Create a note with three ## sections, the middle one containing the special character in its header name
2. Call bear-replace-text with scope=section targeting that header
3. Wait 500ms for Bear to process
4. Read the note back with bear-open-note and check whether the section content changed
5. Archive the test note

All 4 failing characters exhibit the same behavior: bear-replace-text reports success, but bear-open-note shows the original section text unchanged.

Root cause hypothesis

Bear's x-callback-url handler parses these characters structurally before decoding percent-encoded values in the header parameter:

• & is treated as a query parameter delimiter — header=Q&A Section becomes header=Q plus an orphan parameter A Section
• / likely confuses internal URL path routing
• [ ] have special meaning in RFC 3986 (IPv6 literals)
• | is not valid in URIs; some parsers reject or mangle it

Impact

Section-level content replacement (/add-text?mode=replace&header=...) is unreliable for any note with these characters in section headers. Full-note-body replacement (mode=replace without header) is not affected.

Workaround

Perform section replacement client-side: read the full note, splice the section content in markdown, then use mode=replace without the header parameter to write the entire modified body.

[vasylenko]

Migrated to Linear (SVA-7). Closing this issue.