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

Annotations cover safety (readOnly false, destructive false, idempotent false), so the description adds behavioral context: primary_email must be valid and unique across contacts, creation triggers a lead job, and the change is attributed to the caller. However, the lead-job phrasing ('opens the lead's Work a new lead job at birth') is cryptic and may confuse rather than clarify.

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?

Three sentences, with purpose and key constraint front-loaded. The second sentence is awkward and unclear, but overall the definition is compact and avoids repetition. Some phrasing ('at birth', 'as the contact page does') adds noise.

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?

Given a 4-parameter create tool with zero schema descriptions and no output schema, the definition is incomplete. It omits optional fields entirely and does not describe return values or permissions. The side-effect disclosure is helpful but insufficient to fill the 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%, so the description carries full burden. It clarifies primary_email as required, valid, and unique, but says nothing about phone, company, or full_name. Three of four parameters remain undocumented, leaving a significant gap.

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 verb and resource: 'Create a contact.' It also references parity with the contact page UI, which reinforces the purpose. The resource 'contact' clearly distinguishes it from sibling create tools like create_deal or create_a_form.

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 explicit when-to-use guidance or alternatives are provided. It implies the tool is for creating contacts, but doesn't say when to choose it over restore_contact, update_contact, or other contact-related siblings. The phrase 'as the contact page does' hints at UI parity but is not a usage rule.

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