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

Goes well beyond annotations by disclosing concrete side effects: which statuses 'end every open job on the lead' and which 'open the lead's job when none is open', plus the audit behavior ('on the lead's timeline under whoever made it'). Annotations only carry safety hints (idempotent, non-destructive), so this extra side-effect detail is genuinely additive.

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, each doing distinct work: vocabulary mapping, side effects, and audit trail. Front-loaded with the core action; the parenthetical '(a person working it by hand)' is slightly cryptic but not wasteful enough to penalize heavily.

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?

With no output schema and annotations covering only safety hints, the description supplies the mutation consequences and audit behavior an agent needs. It is close to complete; only the omission of any mention of the optional 'because' timeline rationale leaves a minor gap.

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 67%; the schema documents 'because' and 'contact_id', and the description enriches the status enum with human-readable labels and per-value consequences. It adds real meaning over the raw enum, though it says nothing about 'because' beyond what the schema already provides.

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 precise verb+resource ('Set a lead's status') and enumerates the exact status vocabulary, so the agent knows precisely what is being mutated. It does not explicitly distinguish itself from the adjacent sibling update_contact, but the intent is unambiguous.

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 phrase 'as the contact page does' anchors usage to the known UI behavior, and the status list implies the contexts in which each is used. However, it never states when to use this tool versus update_contact or other contact-mutation siblings, leaving routing to inference.

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