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

Annotations already declare readOnlyHint=false, idempotentHint=false and destructiveHint=false, so the safety profile is covered. The description adds value beyond that by spelling out the consequence of non-idempotency (duplicate records) and the mitigation workflow, plus the underlying HTTP endpoint. It stops short of saying what the call returns or what permissions/validation errors to expect.

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 short sentences, front-loaded with the WRITE marker and the resource, then the duplicate-risk warning and the alternative, then the endpoint. No filler; every clause carries information.

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?

With 13 loosely documented parameters and no output schema, the description should at minimum explain which fields identify a supporter and what comes back (e.g., the new supporter ID) so a caller can chain into funraise_get_supporter. Neither is addressed, leaving meaningful gaps for a create operation.

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 8% across 13 parameters with zero required fields, so the schema alone leaves field intent largely undocumented. The description contributes nothing about parameters — no indication of which fields are needed, how email uniqueness works, or what the tags string format means — so it fails to compensate for the coverage gap.

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?

Opens with 'WRITE: create a supporter (donor) record in Funraise' — a specific verb, resource, and side-effect class, plus the concrete endpoint POST /api/v1/crm/supporter. An agent can distinguish it from the many funraise_get_* and funraise_list_* siblings without opening any 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?

Explicitly states the workflow precondition: 'search with funraise_list_supporters (email) first to avoid duplicates', naming the exact alternative tool and the parameter to search by. It also states the condition that makes this necessary ('creates a new record each call').

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