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

With no annotations, the description carries the full burden and does well: it discloses sources, that each sense is labeled with its source, and that the result is empty for unknown words or when no dictionary is loaded. It omits richer output/format detail but covers the key behavioral edge cases.

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 a category tag and a one-line essence ('what an English word MEANS'), followed by sources, edge case, and sibling routing. Dense but each clause carries information; no filler.

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 must explain returns, and it does — senses labeled by source, empty on unknown words. For a single-param lookup tool this is nearly complete; only return format/structure detail is left unspecified.

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 single 'word' param is self-evident and at 0% schema coverage the description compensates by specifying it must be an English word and noting the unknown-word edge case. It adds the meaningful constraint the schema lacks, though no format/length guidance beyond the schema.

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: the dictionary meaning of an English word, with named sources (Webster's 1913 + supplement). It explicitly distinguishes itself from thesaurus (synonyms) and word_study (original languages), so an agent can route without opening any 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?

It names the alternatives (thesaurus, word_study) and states the boundary — define handles English word meaning and 'points to them, never duplicates'. This gives clear routing context, though it stops short of explicit when-not conditions (e.g. non-English terms).

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