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

Annotations already flag destructiveHint=true and idempotentHint=true; the description goes beyond them by disclosing the refusal path for sync-sourced and owner-locked fields, that the error names the offending fields, and the two remedies (change at source, or rebind the smart field). It omits whether omitted parameters are left unchanged, which matters for a destructive update.

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 compact sentences front-loaded with the action, then the failure mode, then the remedy. No filler, though the opening sentence is generic enough that it could have named the writable field set instead.

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?

No output schema exists, and the description covers the key failure mode and its recovery. It still leaves the partial-update question open (does specifying only name wipe email/phone?) and says nothing about what a successful response contains, which is a meaningful gap for a destructive mutation.

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 the schema already explains all seven parameters, including that id comes from list_teammates. The description adds only a cross-cutting constraint on which fields are writable, not per-parameter meaning, so baseline 3 applies.

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?

States a specific verb and resource ('Change a teammate's values'), which clearly separates it from create_teammate, delete_teammate and the other update_* siblings. It does not enumerate which values are changeable, but the schema covers that fully.

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?

Usage is implied (edit an existing teammate rather than create/delete one) and the description identifies the prerequisite that a field must not be sync-bound or owner-locked. It never explicitly says when to reach for this versus get_teammate or update_smart_field, leaving routing to the naming.

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