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

With annotations covering safety (readOnlyHint=false, openWorldHint=true, destructiveHint=false), the description adds strong extra context: it returns a person_id, can trigger lead follow-up workflows, requires per-call confirmation by default (switchable off), and needs a Cotlet API key with app access. These are genuine behavioral disclosures beyond the structured fields.

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?

Front-loaded with the core action, but the confirmation topic is stated twice ('By default you confirm each call' and 'Reaches other people: confirm with the user before each call'), which is redundant and slightly muddies the instruction.

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 mutation tool with no output schema, the description covers the return value (person_id), the workflow side effect, the confirmation requirement, and the auth prerequisite. It omits error/failure behavior, but overall it is complete enough to call safely.

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 description coverage is 100% with 5 documented parameters, so the schema already carries parameter meaning; the description only gestures at 'contact details and source' without adding format or syntax detail. Baseline 3 is appropriate.

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 ('Add a lead with contact details and source') and clarifies it adds exactly one prospect returning a person_id. This cleanly distinguishes it from sibling zen-planner_list_prospects, though it never names siblings explicitly.

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 real context ('If your studio has lead follow-up workflows set up... a new prospect can start them'), which tells the agent a side effect to expect but not when to prefer this over alternatives like promote_rank. No when-not guidance.

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