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

Annotations already declare readOnly, idempotent, and closed-world, so the safety bar is met. The description adds genuine context beyond that: it preserves ambiguity rather than interpreting intent, and it discloses that text goes to a reference server and never to an LLM, which is a meaningful data-handling note.

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?

Three short, front-loaded sentences, each carrying distinct information: purpose, behavioral stance, and data-handling. Zero 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 only two fully documented parameters and no output schema required (per rules, return values need not be explained), the description covers purpose, behavior, and privacy adequately. It is slightly thin on when to prefer this over sibling lookup tools, but otherwise complete.

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 100%, so both parameters (text, include_mature) are already documented with constraints and defaults. The description adds no syntax or format detail about either parameter, so the baseline of 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?

The description gives a specific verb+resource: 'Find documented slang in a phrase.' Combined with the name decode_phrase, an agent understands this is a decode/lookup operation. It does not explicitly distinguish itself from lookup_term or search_terms, so it is clear but not sibling-differentiated.

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?

'Preserves ambiguity; not an interpretation of speaker intent' implies when the tool is appropriate (documented reference lookup rather than intent inference), but it never names an alternative sibling or states an explicit when-not condition. Usage is inferable but not spelled out.

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