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

Annotations already declare destructiveHint=true and openWorldHint=false, so the safety profile is covered structurally. The description adds useful behavioral detail that `starred` is a contact setting not a list column and that archiving lives elsewhere, but says nothing about permission requirements, reversibility of overwritten field values, or partial-update semantics for a destructive mutation.

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 compact sentences with no filler, and the core action is front-loaded. The opening 'Update a Lead - Update lead/contact properties' is mildly redundant with itself but does not waste meaningful space.

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?

Covered well for a 9-parameter mutation with full schema coverage and an output schema, especially since naming convention and field-vs-setting distinctions are spelled out. The main residual gap is behavioral: overwrite vs merge semantics and permission expectations are unaddressed.

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 already 100%, so the baseline would be 3; the description adds genuine value by stating that all field names use snake_case with examples (first_name, company_name, lead_score), which matters because additionalProperties is false and custom fields are not enumerated in the schema. It reinforces the `starred` semantics but adds nothing on `workspace_id` defaulting beyond what the schema says.

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 and resource ('Update a Lead - Update lead/contact properties including custom fields') and explicitly routes archiving to the archive_contact sibling. It does not distinguish itself from other lead-mutating siblings such as move_lead or unsubscribe_lead_from_sequence, so it stops short of a 5.

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?

Gives an explicit exclusion boundary: 'Contact archiving is handled by archive_contact,' which tells the agent when not to use this tool. It also clarifies that `starred` is a setting rather than a column, but provides no positive guidance on when to prefer this over other lead tools.

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