add_contact

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

With no annotations, the description bears full burden for behavioral disclosure. It only states 'Add a contact', omitting critical details like idempotency (e.g., duplicates), error handling, required permissions, or what happens on failure. This leaves the agent unaware of potential side effects.

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?

The description is a single, front-loaded sentence with no redundant words. Every word earns its place; it is appropriately sized for the tool's simplicity.

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?

Despite having 4 parameters including a nested object ('custom_fields') and no output schema, the description provides no information about return values, success indicators, or usage constraints. For a tool with moderate complexity, this is insufficient for complete understanding.

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?

Since schema coverage is 100% (all four parameters have descriptions in the schema), the baseline is 3. The description adds no additional parameter context beyond the schema, so no extra value is provided.

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?

The description clearly states the verb 'Add' and the resource 'contact to your SendGrid marketing contacts', effectively distinguishing it from sibling tools like 'add_contacts_to_list' and 'add_global_suppressions'. However, it could be slightly more explicit about the scope, e.g., whether it's a single contact or bulk.

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?

No guidance is provided on when to use this tool versus alternatives such as 'add_contacts_to_list' or 'delete_contacts'. The description lacks context about prerequisites (e.g., existing list) or scenarios where other tools are more appropriate.

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