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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds useful context beyond that: the newest-first ordering, the specific fields returned, the meaning of the draft status, and an authentication prerequisite ('Needs the user's Cotlet API key with access to this app').

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?

The description has a genuine redundancy: the title-style lead sentence and the second sentence both restate 'customer, total and status, newest first.' The auth note is useful, but the repetition consumes space without adding information.

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 read-only list tool with no output schema and only optional parameters, the description covers ordering, returned fields, status meaning, and auth requirements. It is nearly complete, though it does not mention pagination behavior tied to the limit parameter.

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 limit, status, and customer_id are already documented in the schema, establishing a baseline of 3. The description adds a little meaning to one enum value (draft = not sent) but does not elaborate on limit ranges, customer_id format, or the 'all' status beyond what the schema states.

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 ('Lists estimates') and describes the returned fields (customer, total, status) plus ordering. It is distinguishable from the sibling create/send tools, though it never names them directly. The opening fragment 'Yardbook: Estimates with customer, total and status, newest first' largely duplicates the following sentence.

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 clarifies status semantics (draft = not sent) and notes the downstream path ('Approved estimates can be turned into an invoice with create_invoice'), which implies when a list like this is relevant. However, it gives no explicit guidance on when to call this vs alternatives such as yardbook_get_invoice or yardbook_list_invoices.

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