check_entity

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

With no annotations, the description carries the full burden. It discloses the return format ('recorded state series with dates and sources'), the non-advice nature, and the honest failure behavior for unknown/fabricated subjects ('clean not_observed, never a fabricated result'). It stops short of stating rate limits or data freshness, but for a read-only lookup these are minor omissions.

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?

Three sentences, all informative, with the primary subject front-loaded in the first sentence. No filler or redundancy. Each sentence adds a distinct layer: subject, return content, and failure semantics.

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?

For a tool with only two parameters and no output schema, the description covers the essential lookup behavior, return value nature, and not-found semantics. It does not detail what a 'survival observation' looks like structurally, but the phrase 'state series with dates and sources' gives enough shape. This is well complete for its simplicity.

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 coverage is 100%, with both slug and live documented in the input schema. The description adds marginal semantic value by clarifying the subject scope and the return concept, but it does not go beyond what the schema already provides. Baseline 3 is appropriate because the schema handles parameter documentation adequately.

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 and resource: 'Dated survival observation(s) for ONE owner/repo' from lastseen.dev. It clearly distinguishes itself from siblings by scoping to a single owner/repo and explicitly calling out its lookup nature. The example 'actions/checkout' and the return of a 'recorded state series' make the function 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?

The description gives clear usage context: it is for one specific repo ('ONE owner/repo') and is a 'Lookup, not advice.' It also warns about unknown/fabricated subjects returning not_observed, which helps set expectations. It does not explicitly name alternatives like check_org or check_manifest, but the singular repo scope implies when this tool is appropriate.

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