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

Annotations declare readOnlyHint=true, but the description states the tool 'creates its monitor' and sends start/fail/exit-code signals — clear state mutation and resource creation. This directly contradicts the read-only annotation, so the safety profile is actively misleading rather than merely incomplete.

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 core action and reasonably sized, but the sentence 'the first signal of a new name creates its monitor' is essentially repeated twice, and the cron/tz/grace_sec clause adds detail of limited use. Some of the length does not earn its place.

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 should ideally indicate what the agent gets back (e.g., success/noop/created). It thoroughly covers input behavior and monitor-creation semantics but is silent on return values, leaving an agent guessing about the response of a signaling call.

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 100%, so slug, signal and ingestKey are already documented. The description adds context (the slug 'becomes the monitor name', shared cron/tz/grace_sec rules) but no new syntax or format detail beyond the schema, so the baseline 3 for full schema coverage 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 (send start/fail/exit code) and resource (a monitor identified by slug name), and explicitly distinguishes itself from the id-based variants by quoting the equivalent `/in/:id/...` endpoints 'for a fleet that only knows the ingest key: the job sends its name, not the monitor id.' An agent can differentiate it from signal_start/signal_fail/signal_exit_code/ping_slug without opening a schema.

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?

Gives a clear selection context: use this when the fleet only knows the ingest key and sends a name rather than a monitor id. It does not explicitly name the sibling alternatives (signal_start, signal_fail, signal_exit_code) or state when NOT to use it, so it stops short of full when/when-not/alternative coverage.

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