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

With no annotations provided, the description carries the full burden and does an excellent job. It discloses side effects (writes to metadata.proof, auto-creates a next-move action based on outcome), idempotency, and authentication requirements (no API key needed). This goes above and beyond what a typical description provides.

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?

The description is compact and front-loaded, opening with a clear action statement, then usage guidance, side effects, idempotency, and auth. Every sentence adds value without unnecessary fluff, making it easy to scan and understand quickly.

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?

Despite no output schema and no annotations, the description covers everything needed: purpose, trigger conditions, process, side effects (including decision tree for trending/engaged/stalled), idempotency, and authentication. It is sufficiently complete for an agent to decide when and how to invoke this tool.

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 the baseline is 3. The description adds some context by explaining that actionId references a publishedUrl pointing at an HN post and that force bypasses an existing measurement, but it does not provide detailed parameter syntax beyond the schema. It neither fully compensates nor detracts.

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 clearly identifies the specific verb+resource: it pulls a Hacker News post's score, comments, and top replies via the public HN API and writes them to metadata.proof. It distinguishes itself from sibling tools like chieflab_measure_reddit by explicitly targeting Hacker News and describing the unique follow-up behavior.

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 description provides explicit guidance on when to use the tool: 'USE WHEN a published Hacker News action is ripe for 24h measurement.' It explains the prerequisite checks (publishedUrl, item id, Firebase API) and mentions idempotency, but does not explicitly name alternative tools or state when not to use it, stopping short of a 5.

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