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

With no annotations, the description carries the full burden and does well: it discloses the auth model (signing_secret as Bearer, no agent key needed), the return values (run_id, deadline), and idempotency behavior when run_id is supplied. It only weakly implies the default superseding side-effect without run_id, so it falls short of a 5.

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?

Four compact sentences, front-loaded with purpose then return values, auth, and the optional parameter's semantics. No filler, though the ordering of the auth detail before the run_id note is slightly less than ideal.

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?

No output schema exists, and the description fills that gap by naming the returns (run_id, deadline). Auth, idempotency, and the optional parameter are covered; only the default supersede behavior and watch_id semantics remain thin.

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?

Schema description coverage is 0%, so the description must compensate. It explains run_id thoroughly (optional, 1-64 chars, retry-safe) and clarifies signing_secret's role as the Authorization bearer token. watch_id is left undocumented, but its meaning is clear from context.

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?

The description states a specific verb+resource: 'A run began on an overrun watch', which maps to starting a run and is distinguishable from siblings overrun_finish and overrun_watch. It does not explicitly name an alternative sibling, but the resource is unambiguous.

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?

Usage is implied by the tool's role (starting a run) but there is no explicit when-to-use vs when-not, nor a pointer to overrun_finish or overrun_watch. The idempotency note hints at retry scenarios but doesn't frame guidance.

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