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

Annotations already flag destructiveHint=true and idempotentHint=true, and the description adds genuinely new behavior: omitted fields are preserved, a supplied examples list replaces the existing one, and 'The previous text is replaced.' That clarifies the exact blast radius of the destructive hint. It stops short of stating that meaning_index doesn't shift or how an out-of-range index fails.

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 sentences, front-loaded with the target and addressing scheme, followed by the update and replacement semantics. No filler or restatement of the title.

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 a full output schema and complete parameter documentation, the description carries only the burden of update semantics, which it covers. Minor gap: nothing about failure modes for an invalid meaning_index or about interactions with reorder_meanings.

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 the baseline is 3, and the description adds meaning: the target is selected by position, and only supplied fields are written. It reinforces the replace-vs-merge semantics of examples and gloss beyond the per-property descriptions.

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 ('Changes one meaning of a word') and immediately names the addressing scheme (position in the word's card) plus the mutable fields (text, gloss, examples). This clearly separates it from update_word (whole word) and add_meaning/remove_meaning in the sibling list.

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?

The description implies when to use it by explaining partial-update semantics ('Fields not given stay as they are'), but it never names alternatives such as add_meaning for new meanings, remove_meaning for deletion, or reorder_meanings for position changes. The agent must infer the boundary from the sibling names alone.

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