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

Annotations already declare readOnlyHint, idempotentHint and closed-world behavior, and the description redundantly says 'Read-only,' which earns no credit. It does add genuine behavioral context: matching is over gloss words rather than definitions, and a non-match yields an empty list rather than an error. Missing details on ambiguity when multiple items match.

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?

Purpose is front-loaded in the opening clause, and the field enumeration is justified because there is no output schema. The sentences are long and noun-heavy ('the members of the grammar and the terms of the registered dialects'), costing some readability.

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?

With no output schema, the description carries the return contract and does so fully: item fields (written, identifier, form, gloss, kind, category, class, sort, definition) and the empty-list case. For a single-parameter lookup this leaves nothing an agent needs unanswered.

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 a described string parameter, so the baseline is met by structure alone. The description adds real semantics beyond the schema: the term may be a key, form, identifier, or a single English gloss word, and explicitly not a definition word.

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 and resource ('Find the words ... that a term names') and enumerates the three searched collections (lexicon, grammar, registered dialects) plus the matchable fields (key, form, identifier, gloss word). This is far more precise than the bare name 'lookup' and clearly separates it from mutating siblings like write.

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?

Gives an explicit precondition: 'Use it to find the written value of each content word before calling write,' which ties the tool to a workflow step. It does not name alternatives or exclusions (e.g., when to prefer gloss or normalise instead), so it stops short of full when/when-not guidance.

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