Create a lead

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

Adds real behavior beyond the idempotentHint annotation: it discloses the deduplication key (phone number), the differing status codes (201 vs 200), and how to detect which branch occurred. That is substantive, though the phrasing 'check the tool's isError/status if that distinction matters to you' is vague about the actual mechanism.

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?

A single front-loaded sentence that gets the primary action out first, with the status-code detail in a compact parenthetical. Nothing is wasted, though the trailing aside about isError is slightly chatty.

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 5-parameter mutating tool with no output schema and only an idempotentHint annotation, the description covers the idempotency semantics well but leaves the remaining parameters undocumented and says nothing about validation or required-field consequences. Adequate but with clear gaps.

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 0% across 5 parameters, so the description carries the full documentation burden, yet it only describes the role of 'phone' (the match key). The other four parameters (name, tags, email, source) get no meaning, format, or requiredness guidance anywhere.

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 ('Creates') and resource ('a lead') and goes further by describing the upsert branch, which clearly separates it from siblings like list_leads or get_lead_for_call. An agent knows exactly what this tool produces 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?

The upsert behavior implies usage context (safe to call without checking existence first), but there is no explicit when-to-use/when-not-to-use statement and no named alternative for the lookup-only path. Guidance is inferable but not spelled out.

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