Registry/resolve race: insert_text can fail as Unknown tool: cdpInsertText while other CDP verbs work

[Trace824]

Summary

When MCP dispatches insert_text, the wire verb is cdpInsertText. Under extension service-worker load races, registry resolve can return null for that verb even though other CDP tools (e.g. click_at → cdpClickAt) succeed. Callers then see Unknown tool: cdpInsertText.

Repro

• Context: MCP client connected to FSB extension bridge; active tab on x.com compose with Draft.js [data-testid=tweetTextarea_0].
• Steps:
  1. Ensure extension service worker has recently restarted (or reload unpacked extension without full Chrome restart).
  2. Call click_at on the compose field — observe success.
  3. Call insert_text with a short string into the focused compose field.
• Observed: insert_text fails with Unknown tool: cdpInsertText while click_at works.
• Example: compose URL such as https://x.com/compose/post or an in-thread reply composer.

Code pointers (verified against /workspace/FSB)

• extension/ai/tool-definitions.js — insert_text entry with _cdpVerb: 'cdpInsertText' (~L872–886); getToolByNameOrVerb (~L1473) matches _contentVerb / _cdpVerb.
• extension/ws/mcp-bridge-client.js — resolveMcpToolDefinition (~L104); hard /^cdp[A-Z]/ fallback calling executeCDPToolDirect (~L1908–1924).
• extension/content/messaging.js — Unknown-tool path forwards /^cdp[A-Z]/ to background (~L1062–1088).
• extension/background.js — executeCDPToolDirect / cdpInsertText case (~L19786+, ~L20055+).
• mcp/src/tools/manual.ts — fsbVerb = tool._contentVerb || tool._cdpVerb || tool.name (~L252).

Branch fix/navigate-url-truth-and-draft-append already includes the hard CDP fallback and content last-resort; race still needs a durable resolve path + tests.

Proposed fix

Make wire-verb resolve deterministic at dispatch time: always resolve via globalThis.getToolByNameOrVerb (or TOOL_REGISTRY scan) before content routing, and keep the /^cdp[A-Z]/ → executeCDPToolDirect fallback as a non-optional safety net when resolve is null. Root cause is incomplete SW-side verb binding for cdpInsertText under load race, not missing CDP capability.

Acceptance / regression

• After SW restart, insert_text and click_at both succeed on the same compose session without extension reload.
• Unit/integration: resolve cdpInsertText and insert_text to the same tool def; null registry still routes /^cdp/ to executeCDPToolDirect.
• No regression for content-routed tools (type_text, click).

Owner

extension (primary); mcp-server only if wire verb mapping in manual.ts drifts.

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Priority: P1 · Owner: extension

[LakshmanTurlapati]

Fixed in #143: the bridge resolves internal wire verbs like cdpInsertText through the tool registry, so insert_text no longer fails with "Unknown tool".