Remote trigger connectors (Sentry) not available as tools in trigger sessions

Description

MCP connectors attached to a remote trigger via the UI/API are not available to the agent during runs. The agent cannot discover or call connector tools — ToolSearch returns "No matching deferred tools found" for all queries.

Agent reports: "Sentry MCP server is referenced in the project's CLAUDE.md, but it is not currently connected — no mcp__sentry__* tools were found among the available or deferred tools."

Setup

• Trigger with Sentry connector attached
• Connector visible and configured in trigger UI
• mcp_connections present in trigger API response with correct URL and connector UUID

What happens

1. Trigger runs, agent starts
2. Agent tries to call Sentry tools — not found
3. ToolSearch for "sentry", "mcp__sentry__*", "+sentry" etc — all return nothing
4. Only GitHub plugin tools are discoverable
5. Run completes with "MCP tools not available"

What we tried

• Explicit tool names in allowed_tools (mcp__sentry__search_issues, etc.)
• Wildcard patterns (mcp__sentry__*)
• Empty allowed_tools (defaults applied — no MCP tools included)
• Adding ToolSearch to allowed_tools with retry logic
• Adding delay (reading files first) to give MCP servers time to connect
• Re-adding connector in UI
• Various prompt formats (inline, file-based, minimal)

Interesting detail

One early diagnostic run did work — the agent successfully called "Sentry integration" and found 4 issues. All subsequent runs with identical or similar config failed. Suggests a race condition or intermittent connectivity issue.

Environment

• Trigger created via claude.ai UI + API
• Connector: Sentry (https://mcp.sentry.dev/mcp)
• Model: claude-opus-4-6
• Repo: private GitHub repo with sources configured