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

Goes well beyond the destructiveHint annotation: it discloses partial-update semantics ('only the fields you pass change'), a real side effect ('Changing status_name moves it along its workflow (automations may fire)'), and a scope limit ('Cannot delete or archive'). These are the behavioral traits an agent most needs before mutating a record.

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 tight sentences: behavior first, side effect second, constraint third, with the API endpoint as trailing metadata. Every sentence earns its place and the highest-value fact is front-loaded.

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 24-parameter mutation tool with a nested custom_fields object and no output schema, the description covers the essential behavior and side effects. The remaining detail (per-field formats, response shape) is carried by the schema and, appropriately, does not need restating since no output schema exists.

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 100%, so the baseline is 3, but the description adds meaning the schema does not: the partial-update contract for all fields and the workflow effect of status_name. This elevates it above the baseline.

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 (edit) and resource (an existing contact), and the qualifier 'existing' differentiates it from jobnimbus_create_contact and jobnimbus_get_contact. An agent can tell what it does without opening the schema.

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?

Gives clear context (edit fields on an existing contact) and an explicit exclusion ('Cannot delete or archive'), which steers away from delete/archive operations. It stops short of naming alternatives like jobnimbus_create_contact for creating records, so it is a strong 4 rather than a full 5.

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