Add Contact to Segment

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

No annotations are provided, so the description must carry the full burden of behavioral disclosure. It only states the action without mentioning prerequisites, side effects, duplicate handling, or idempotency. For a mutation tool, this is a significant gap.

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 that efficiently states the purpose. It is concise and easy to parse, though it omits important context. It is not overly verbose, so it earns a high score for structure.

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 no annotations, no output schema, and a very short description, the tool is under-specified. It does not explain return values, error conditions, or whether the contact and segment must already exist. For a simple mutation tool, more context is needed to use it confidently.

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?

The schema already provides descriptions for all three parameters (100% coverage), so the baseline is 3. The description adds the 'by contact ID or email' hint, which clarifies alternative identifiers but does not explain their relationship to the required-only segmentId, adding only marginal value over the schema.

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 'Add a contact to a segment' with a specific verb and resource, and adds 'by contact ID or email' to clarify the two identification methods. It distinguishes from the sibling tool 'remove-contact-from-segment'.

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?

The description implies usage context by indicating the contact can be specified by ID or email, but it does not explicitly compare this tool to alternatives or state when not to use it. Sibling tools are not referenced, so the agent gets only implicit guidance.

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