manage_contact

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

The annotations only supply destructiveHint=true; the description adds real behavioral context on top of that, notably that delete is permanent and that update is a partial/PATCH-style change rather than a full replace. It still omits auth/permission requirements and what happens on a bad contact_id, keeping it out of 5 territory.

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 sentences: a front-loaded purpose line followed by a compact per-action bullet list. Every line carries actionable information (required fields, partial-update semantics, permanence) 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 mutation tool with destructiveHint and no output schema, the description covers operation selection, per-action required fields, partial-update behavior, and delete permanence. Missing only error behavior (unknown contact_id) and permission context, which are minor for this scope.

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%, and each parameter's per-action requirement (e.g. 'Required for create.') is already stated in the schema. The description restates these conditionals in one consolidated block, which aids readability but adds essentially no semantics beyond the structured fields, so the 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 set and resource ('Create, update, or delete a saved contact') and immediately enumerates the three operations, so the agent knows exactly what the tool does. It does not explicitly contrast itself with the read-side sibling list_contacts, but the mutation-only scope is unambiguous from the verbs.

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 per-action guidance: create requires phone_number and name, update requires contact_id and only changes passed fields, delete requires contact_id. This tells the agent which operation to select and what each needs. It does not name alternatives (e.g. use list_contacts to look up a contact_id first), so it stops short of a 5.

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