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

Annotations already cover the safety profile (readOnly=true, destructive=false, openWorld=true), so the description's added value is the return shape (ID, name, email, tags) and the auth requirement ('Needs the user's Cotlet API key with access to this app'), both of which go beyond the structured fields. It does not disclose pagination behavior despite a limit parameter, which is the main gap.

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?

Purpose is front-loaded and the follow-up sentences carry real routing and auth information. The 'Tags are the ones you set in Momence.' sentence is marginally redundant filler, keeping it just below a 5.

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 usefully enumerates the returned fields, and it flags the required API key access. Together with 100% schema coverage this is nearly complete; only pagination/result-size behavior is 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 description coverage is 100%, so the schema already documents query, tag, and limit (including the 1-100 range and default 25). The description only restates the same searchable fields and adds no syntax or format detail beyond the schema, so the baseline of 3 applies.

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+resource ('Find customers') and the searchable fields (name, email, phone, tag). It also distinguishes itself from the get_customer sibling by explaining that this tool produces the customer_id that get_customer consumes, so an agent can route between them without opening a schema.

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?

It gives clear operational context for the result ('Use customer_id in get_customer, book_customer and list_customer_payments'), which tells the agent this is the entry point in a lookup workflow. It stops short of explicitly stating when to prefer this over other lookups or any exclusions, so it is a strong 4 rather than a 5.

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