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

There are no annotations, so the description carries the full burden of behavioral disclosure. It does provide useful details: the clocks are 'separate recomputable' and the 'deprecation sweep fails closed on expiry,' implying fail-closed behavior. However, it does not clarify whether the operation is read-only, whether auth is needed, or what the response contains.

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 short and front-loaded with the main subject, but it is dense and jargon-heavy. The closing sentence 'This is not external adoption' is unexplained and likely to confuse an agent rather than clarify scope.

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 zero-parameter getter, the description gives a reasonable inventory of the returned instruments. Yet with no output schema, the agent still lacks guidance on the return shape, and the cryptic negation does not round out the picture.

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?

The tool has zero parameters, so the description cannot add parameter-level meaning beyond the empty schema. Baseline 4 is appropriate, and the description correctly focuses on the domain data returned.

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 names a specific resource ('observatory instruments') and enumerates its contents: corpus attestations, recomputable scanner-schedule and evidence-validity clocks, and the deterministic gate's firing record. This goes beyond a tautology and gives the agent a concrete sense of what the tool returns, though it does not explicitly state the action verb or contrast with sibling tools.

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?

No when-to-use guidance is provided; the description does not state what problem this tool solves or when it should be preferred over siblings like get_adoption_snapshot or get_changelog. The only directional signal is the cryptic 'This is not external adoption,' which is not actionable.

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