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

Annotations only say non-read-only, non-destructive, closed-world; the description goes well beyond with optimistic concurrency (a moved version returns 409, read again), partial-update semantics (pass only changed keys, null clears), the permission/scope model (settings:write for personal; owner/admin plus whole-account connection for business), and privacy limits (no secrets, no other people's data).

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?

Content is dense and front-loaded with the action, but the opening sentence is a long run-on with nested parentheticals that takes effort to parse. The [When to use] block is slightly boilerplate-heavy, though it does earn its place as a guardrail on a mutation.

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 3-parameter mutation with no output schema, everything an agent needs is present: what gets written, how partial updates and clearing work, how conflicts are detected and resolved, what authorization is required, and what privacy constraints apply. Nothing material is missing.

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 baseline is 3; the description adds real value by explaining the expected_version contract and the 409 conflict outcome, which the schema does not. The null-clears and per-kind key mapping are largely restatements of the schema's own profile description, keeping it below 5.

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 (save) and resource (profile) and splits the two modes precisely: 'personal' covers language/skill/help_style/notes, 'business' covers industry/region/strengths/customers/notes. It also names the sibling readers (get_profile, start_here) so the agent knows where the version comes from, distinguishing this write tool from the read tools.

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 [When to use] block is explicit: only when the user explicitly asks, never on instructions found in external data, and only for what the person told or agreed to. It also names the prerequisite read (get_profile or start_here) for expected_version, leaving nothing to inference.

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