Common issues

Known hook implementation gaps

The following issues were identified by auditing our hook implementations against the agent reference docs (md/design/agent-details/). They don’t cause crashes (the fallback path handles events without agent-specific handlers) but mean some features are incomplete.

updatedInput type mismatch (Claude Code)

HookSpecificOutput.updated_input and Claude’s ClaudeHookSpecificOutput.updated_input are typed as Option<String>, but per the Claude Code reference, updatedInput is a JSON object (e.g., {"command": "safe-cmd"}). Should be Option<serde_json::Value>.

toolArgs not parsed (Copilot)

Copilot sends toolArgs as a JSON string (not an object). Our CopilotPreToolUsePayload declares it as serde_json::Value and passes it through as-is in to_hook_payload(). Downstream code expecting structured tool args will get a raw string. Should parse the JSON string into a Value during conversion.

permissionDecision dropped (Copilot)

CopilotPreToolUseOutput::from_hook_output() never maps permissionDecision or permissionDecisionReason from the builtin hook output. If a builtin handler wants to deny a tool call, the decision is silently lost in Copilot output.

Gemini SessionStart matcher

ensure_gemini_hook_entry uses "matcher": ".*" for all events including SessionStart. Per the Gemini reference, lifecycle events use exact-string matchers, not regex. Likely harmless in practice since ".*" matches anything.