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

The annotations already flag destructive behavior and idempotency, but the description adds meaningful behavioral detail: updates propagate across all projects sharing the key, and machine-translation flags are cleared because the value becomes human-edited. This is valuable context beyond the annotations and helps an agent anticipate side effects.

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 sentences, each earning its place: the first states the core operation, the second warns of cross-project side effects, and the third explains flag clearing. The most important action is front-loaded, and there is no redundant or promotional wording.

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 moderately simple 4-parameter update tool with a full output schema and clear annotations, the description covers the operation, shared-key side effects, and flag behavior. Nothing an agent needs to invoke it correctly is missing.

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 all four parameters are already documented structurally. The description adds little new parameter-level meaning beyond reinforcing that key and language identify the specific translation and that value is the new human-edited string. This matches the baseline for fully schema-covered parameters.

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 names the exact action ('update the translation value'), the target resource ('phrase key and language'), and the container ('MultiLocale project'). It also distinguishes itself clearly from sibling tools like add_phrase, delete_phrase, and update_project by stating precisely which object and attribute it modifies.

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 provides clear context: this is for updating an existing translation identified by key and language within a project. It does not explicitly mention alternatives or exclusion conditions, such as 'use add_phrase for new keys' or 'use delete_phrase to remove', so it stops short of the top score but still gives enough situational clarity.

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