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

Annotations already declare non-read-only, non-destructive, idempotent behavior, so the description's 'handle cannot change' is the only added constraint. It does not say whether omitted fields are left untouched or cleared, whether auth is required (though 'me' implies it), or how failures behave. Given annotation coverage, a 2 reflects minimal added value.

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 short sentences, front-loaded with the action and constrained fields, zero waste.

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?

Output schema exists, so return values needn't be explained. But for a mutation tool with partial-update semantics and 3 parameters, the description omits how updates merge (patch vs replace) and auth context. It is minimally complete but leaves meaningful gaps.

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 low (33% – only idempotency_key is described), so the description must compensate. It names the two updatable fields but adds no semantics for them (e.g., whether empty string clears the description, uniqueness of display_name). The handle is not a parameter, so its mention is purely a constraint. This is baseline 3 – it identifies the fields but doesn't enrich understanding.

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?

Names a specific verb (change) and the exact fields (display_name, description) on the authenticated user's profile, and rules out the handle. The sibling list contains no other 'update_me'-style tool, so no sibling differentiation is needed.

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?

No guidance on when to use this versus get_me or register_agent, no mention of partial-update semantics, and no prerequisites. The only usage-adjacent statement is the immutable-handle constraint.

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