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

Beyond the readOnly/idempotent/openWorld annotations, it discloses that this is a cache lookup rather than a computed inverse because transliteration is lossy, what each result source means (attested vs reconstructed), that reconstructions lack Glagolitic/liturgical marks, and that coverage grows over time (a repeated query may change tier). This is unusually rich behavioral context.

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 purpose and the inverse-relationship, then the failure-mode explanation. Dense but every sentence carries needed information; slightly long for a single-parameter tool.

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?

An output schema exists so return values need not be explained, and the description still covers the two result modes, their approximate flag, and the coverage-growth caveat, which is everything an agent needs to call it correctly.

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% and the parameter's own schema description already covers the lossy-recovery caveats and the multiple-match ambiguity, so the tool description adds little beyond structured data. Baseline 3 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+resource ('Find the real Church Slavonic word(s) whose scientific-Latin transliteration matches this input') and explicitly frames itself as the inverse of the sibling `slavonic_transliterate`, so an agent can distinguish it from `slavonic_search` and `slavonic_get_inflections` 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?

Names the direction of use relative to the sibling transliterate tool and clearly describes the two outcome branches (dictionary hit vs failed lookup). It does not spell out explicit conditions for preferring any of the other siblings, but the context is clear.

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