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

Annotations already declare write (readOnlyHint=false), non-destructive, openWorld. The description adds value beyond them: default per-call confirmation with the option to disable, an external-reach warning ('Reaches other people'), and an auth requirement (Cotlet API key with app access). No contradictions. It could say more about duplicate-handling behavior.

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 and readable, but the first two sentences both restate that it creates a customer with name/contact/address, which is redundant. The multi-sentence housekeeping (confirmation, reach, API key) is useful but could be tighter. Some waste reduces the score.

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, the description carries the return-value burden and covers purpose, dedup guidance, confirmation policy, external reach, and auth. For a single-required-param create tool with full schema coverage, this is nearly complete; only duplicate-handling and success behavior are left implicit.

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 schema already documents all 8 parameters, giving a baseline of 3. The description adds the rationale for the mobile field (text-capable vs home/work), but partly restates the schema's own mobile description and references home/work numbers that do not exist as parameters. Net added value is marginal.

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 customer', 'Creates a customer profile with name, email, phone numbers and one service address'), so an agent immediately knows the operation. It references list_customers as a workflow predecessor rather than a same-purpose alternative, so sibling differentiation is only partial. The core purpose 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?

Gives a concrete precondition ('Run list_customers first so you do not add a second profile for someone who already exists') and field-selection guidance for texted numbers. It is clear context but does not enumerate when-not scenarios or other sibling alternatives for creating records in other systems. Solid, above-average guidance.

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