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

Annotations already indicate a non-read-only operation. The description adds the meaningful behavioral detail that this is a partial update—fields omitted are left unchanged. This prevents the agent from assuming a full replacement, which is valuable context beyond what the annotations provide. Side effects and error behavior are not mentioned, but the annotations cover the safety profile.

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?

A single front-loaded sentence with zero wasted words. It states the operation and the most important usage rule efficiently. No redundant repetition of schema details.

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?

Given the complex schema (9 parameters, nested query object), 100% parameter coverage, presence of an output schema, and annotations, the description provides sufficient orientation. The one omission—mentioning that prerequisites like the goal id come from list_goals—is covered by the schema's id description, so the description does not need to repeat it. The tool is well-specified overall.

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 coverage is 100%, so the baseline is 3. The description adds a cross-cutting semantic: only id is required and all other fields are optional partial-update fields, meaning omitted values are preserved. This PATCH-like behavior is not explicitly stated in the schema properties and meaningfully changes how the agent should construct the request.

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 states a specific verb ('Update') and resource ('a goal') with an added key semantic: 'only include the fields you want to change'. This clearly distinguishes it from sibling tools like create_goal, archive_goal, and duplicate_goal, and from other update_* tools for different resource types.

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 no guidance on when to choose this tool versus alternatives (e.g., create_goal for new goals, list_goals to obtain an id). The partial-update instruction is about how to call the tool, not when to use it. No prerequisites or exclusions are mentioned, leaving the agent to infer from the tool name.

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