sendgrid_list_contacts

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds a meaningful scope qualifier by specifying 'marketing' contacts, distinguishing them from transactional/sender identities. It does not mention pagination, result caps, rate limits, or required API key scopes, which matter for a bulk list call.

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?

One short sentence with the resource scope front-loaded and zero filler. Nothing is redundant or buried.

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 one-parameter read tool with rich annotations and no output schema, this is close to adequate, but 'all' is unqualified: the agent is not told whether results are paginated, capped, or returned as a flat array, which affects how it should handle the response.

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?

With a single parameter at 100% schema description coverage, the schema already documents api_key fully. The description adds no syntax, scope, or permission detail about the key beyond what the schema states, so the baseline of 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 (list), resource (marketing contacts), and platform (SendGrid), with the qualifier 'all' implying no filtering. It is clearly distinct from sendgrid_add_contact and sendgrid_send_email, though it does not explicitly name those siblings.

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?

'List all' hints that this is a bulk retrieval with no filter options, which implies the agent should not expect search semantics. However, there is no explicit statement of when to prefer this over add_contact's return data or any other contact-fetching path, and no prerequisites or exclusions are given.

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