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

No annotations provided, so the description carries full burden. It discloses the write operation, the specific writable fields, OAuth requirement, and that the saved values affect later calls. It does not mention error conditions or idempotency, but covers key behavioral traits well.

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?

Two sentences, front-loaded with the main purpose. No wasted words. The second sentence efficiently clarifies scope and auth. Excellent structure.

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 4 optional parameters, no output schema, and no annotations, the description covers the essential context: purpose, writable fields, auth, and persistence behavior. It lacks mention of what happens if all parameters are omitted, but overall it is sufficient for a simple update tool.

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% with good descriptions for each parameter. The description adds context that these fields constitute the 'synthesis profile' and clarifies that null for age means adult baseline. This adds value beyond the schema.

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 states the verb 'Save' and the resource 'signed-in user's synthesis profile' with specific fields. It explicitly distinguishes from siblings by noting what is NOT writable (favourites, cities, history), making its scope precise.

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 explains when to use (to persist profile values for future calls) and implicitly when not to (for updating cities/favourites). It also mentions the required OAuth scope. However, it could more explicitly name alternative tools for non-profile updates.

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