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

With readOnlyHint=true, idempotentHint=true, and destructiveHint=false already present, the description adds some context beyond annotations — namely the 'published' qualifier (implying unpublished versions may not be readable) and the exact-match semantics on subject/object. It doesn't address error semantics or what happens for missing/updated values, but it's consistent and modestly additive. No contradiction with annotations.

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?

One sentence, ~22 words, front-loaded with the verb 'Read,' and every phrase earns its place — 'published,' 'exact,' and the field enumeration all convey meaning. No fluff or repetition of the tool name.

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 single-ID read-only getter with a rich output schema and full annotation coverage, this is nearly complete. The only gap is the unp Explored 'published' semantics — how unpublished assertions are handled — but given the low complexity, the description is adequately scoped.

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% and the description never mentions compatibility_id. The parameter name is self-explanatory and the single-ID lookup pattern lowers the cost of omission, but by the rubric the description must compensate when coverage is low, and it does not. A short gloss on the ID's provenance or format would have helped.

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?

Uses a specific verb ('Read') plus a clear resource ('one published compatibility or substitution assertion') and a precise scope ('exact subject, object, conditions, confidence, evidence source, and observation time'). Clear and specific, though it doesn't explicitly differentiate itself from the sibling get_* tools — though no sibling overlaps with 'compatibility' domain, so the omission is minor.

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 guidance on when to use this tool versus an alternative. There's no mention of when not to use it, no alternative tool names, and no conditions under which a different read path (e.g., search or list) would be preferable. Implied usage only via 'one' and 'published.'

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