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

Annotations only give destructiveHint=true; the description goes further by disclosing that the update is partial ('only fields you pass change') and that multi-value fields (email, phone, address, website) are REPLACED wholesale — the single most important data-loss behavior for an agent to know. It omits auth/permission requirements and any rate or idempotency notes.

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?

Four compact sentences, front-loaded with the destructive replace warning, and every clause carries non-obvious information. No filler.

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 13-parameter mutation with no output schema, the description covers the highest-risk unknowns (partial update, replacement semantics, is_company coupling). What remains unstated — permission requirements and what the response returns on success — is minor but not trivial for an edit operation.

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 100%, so the baseline is 3, but the description adds real meaning the schema does not: the partial-update rule, the replace-not-merge rule for multi-value lists, and the specific instruction to set is_company=true when renaming a company (which reframes the schema's terse 'set true if this record is a company' text).

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 fields on an existing contact or company'), and 'existing' implicitly distinguishes it from the sibling lacrm_create_contact. It never names get_contact or create_contact explicitly, so it stops short of full sibling differentiation.

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?

Usage is implied by the semantics — agents can infer this is the tool for modifying an existing record vs. lacrm_create_contact — but no sentence states when to use it, when to prefer lacrm_search_contacts to find the id first, or when to fall back to field-specific tools. Adequate but guidance is left to inference.

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