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

Annotations already establish that this is a read-only, closed-world, non-destructive operation. The description adds useful behavioral context by specifying that the card includes meanings, examples, collocations, notes, user progress, notebook schedule type, and smart-notebook retention probability. It lacks operational details such as error behavior when word_id is invalid.

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?

The description is a single front-loaded sentence with no irrelevant filler. It is dense but well structured, though some detailed return-content clauses overlap with what the output schema can provide.

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 one-parameter read-only tool with full schema coverage, annotations, and an output schema, the description is sufficiently complete about what the card contains. It is only incomplete on when to choose this over sibling retrieval tools.

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%, and the sole parameter word_id is already documented as an id from another tool's result. The description adds no parameter-specific meaning beyond the schema, 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 clearly identifies a single-word retrieval tool and enumerates the card contents, so the agent can tell that it fetches full detail for one word. It does not explicitly contrast this with siblings such as list_words or search_words, which keeps it from a 5.

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?

Usage is implied: call this when full detail for one known word is needed. There is no explicit when-to-use guidance, no mention of using another tool to obtain word_id, and no exclusions or alternatives.

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