Get incident timeline

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Beyond the readOnly/idempotent annotations, the description discloses non-obvious behaviors: the required read scope, the fact that run_* events are matched on the run id captured at opening (so absence means no run was recorded), that delivery error text is deliberately omitted, and that untrusted_fields flags data LastPing did not write. These are exactly the kind of gotchas annotations cannot carry.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with the precondition, then purpose, then behavioral caveats; every sentence carries information. The mid-sentence enumeration of timeline event types is dense but earns its place by telling the agent what to expect in the response.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description itself must describe the return shape, and it does: the ordered event vocabulary, the destination/attempts detail, the alerts-only caveat, and the untrusted_fields semantics. An agent has enough to call and interpret this correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

A single parameter with 100% schema coverage, so the schema already documents incident_id and even its source (list_incidents, list_open_incidents, add_incident_note). The description adds no format or edge-case meaning for the id, so the baseline of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource — 'Gets one incident and its ordered timeline' — and enumerates the timeline event types, which separates it from the run-history siblings like get_run and get_run_history. It never names a sibling explicitly, so the differentiation is inferable rather than stated.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The framing 'For what the run was doing, who was paged and what was tried' implies the investigative use case, and the read-scope prerequisite is stated. However, there is no explicit when-to-use guidance versus list_incidents, list_open_incidents, or get_run, leaving the agent to infer which tool answers which question.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.