The hosted Streamable HTTP tools/call boundary emits one fail-open PostHog
event named MCP Tool Call per attempted tool call. It is the source for MCP
adoption and retrieval dashboards; do not rename its properties without a
dashboard migration.
| Property | Values / meaning |
|---|---|
tool |
Allowlisted MCP tool name, otherwise unknown. |
operation |
Closed retrieval grouping such as memory_search, memory_list, conversation_get, or the connector-ready memory_conversation_search / memory_conversation_fetch. |
client |
chatgpt, claude, other_registered, api_key, or unknown; never the raw OAuth client ID. |
transport |
hosted_oauth, api_key, or unknown. |
outcome |
success or error. |
authorization_outcome |
allowed, denied, or not_applicable. |
error_category |
none, authorization_denied, validation, unknown_tool, or internal. |
duration_ms |
Tool execution duration, capped at 60,000 ms; use it for p50/p95. |
result_count |
Top-level result cardinality, capped at 1,000. |
PostHog's distinct ID is the server-side user ID so unique-user counts are available. Event properties intentionally exclude tool arguments, query text, memory and conversation content/IDs, OAuth/API-key credentials, raw client IDs, email, and IP address.