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

Annotations already declare readOnlyHint, openWorldHint and non-destructive, so safety is covered. The description adds genuinely useful context beyond them: it returns contact details and requires a Cotlet API key with app access. It omits pagination/limit behavior and match granularity, keeping it out of 5 territory.

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 tight sentences, front-loaded with the core action, then downstream workflow, then the auth requirement. Every sentence carries information the agent needs; 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?

With no output schema, the description appropriately hints at the return shape ('matches with contact details') and names the key field (customer_id) the agent will chain on. Auth requirement is disclosed. Slightly thin on match behavior/ambiguity handling, but complete for a simple search tool.

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 both parameters (query, limit) are fully documented in the schema. The description restates the searchable field types but adds no syntax or format detail beyond what the schema already provides; 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 (search) and resource (customers) plus the exact searchable fields (name, email, phone), and notes it returns matches with contact details. An agent can distinguish it from get_customer (lookup by ID) and add_customer_note without opening either 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?

Gives clear context for use (searching your list by name/email/phone) and explicitly tells the agent what to do with the results, routing the customer_id output into get_customer, add_customer_note and create_appointment. It does not explicitly contrast with the sibling get_customer for ID-based lookup, so not quite a 5.

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