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

With no annotations present, the description carries the behavioral burden. It discloses two non-obvious traits: the find-or-create pattern (mutation may or may not occur) and idempotency with no double-counting. It does not mention side effects of the lead-outcome beyond recording it, but the key behavioral risk is adequately covered.

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?

Two short sentences deliver the core behavior, the identity key, and the crucial idempotency trait with zero waste. The opening phrase 'Capture a lead' immediately anchors the tool's purpose.

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 tool with no annotations and no output schema, the description is missing essential context: what 'source' means despite being required, whether username/displayName affect behavior, and what the return value communicates. An agent could call it correctly only by inferring these details.

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%, so the description must compensate. It explains that platform and platformUserId form the identity for find-or-create. However, the required 'source' parameter is only an enum with no meaning explained, and the optional username/displayName are not addressed at all, leaving an agent unsure what values to supply.

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 states a specific resource (a lead/contact), the key identity tuple (platform, platformUserId), and the action (find-or-create and record a lead-outcome). This fully distinguishes it from the sibling tools, which are about flows, scheduling, publishing, and analytics rather than lead capture.

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 gives clear context for when to use the tool: any time a lead needs to be captured from a platform user identity. It does not list exclusions or alternatives, but no sibling tool competes for the same job, so an agent can confidently select it without further guidance.

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