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

Annotations only indicate readOnlyHint=false, so the description carries the burden of behavioral detail. It adds valuable context: timezone must be IANA, with translation examples, and requires confirming what was set in the reply. It does not describe side effects (e.g., validation), but for a profile update these are minor. It meaningfully supplements the annotation.

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, dense paragraph that front-loads the purpose and then delivers critical usage rules. Every sentence adds value: the field list, the selective-passing rule, the timezone translation guidance, and the confirmation requirement. It's concise with no filler.

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 7-parameter mutation tool with no output schema and low schema coverage, the description covers the essential usage nuances: which fields to include, the timezone translation requirement, and the confirmation expectation. It doesn't explain how to handle other fields (like first/last name) but those are self-explanatory. It's sufficiently complete for correct invocation.

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 only 43% (3 of 7 properties have descriptions). The description compensates by mapping user-facing terms to schema fields (e.g., 'company website' → website, 'X handle' → twitter_username) and gives deep guidance on timezone formatting and translation. It adds significant meaning beyond the schema, especially for timezone.

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?

Clearly states the tool updates the user's own profile fields, listing specific fields (timezone, name, headline, company website, LinkedIn URL, X handle). It distinguishes from siblings by scoping to 'own profile' and enumerating exact fields, making its purpose unambiguous.

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?

Provides clear guidance on when to use it ('when they ask' for those fields) and explicitly instructs to only pass fields the user asked to change. While it doesn't name alternative tools, the field-specific scope makes misuse unlikely; the instruction on selective parameter passing is a strong usage guideline.

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