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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so safety is covered. The description still adds value by disclosing what the records contain (including the status lifecycle draft/not_sent/sent/approved/invoiced/declined/voided) and the resulting-invoice linkage, which is not derivable from the annotations or input schema.

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?

A single dense sentence plus the endpoint path, with the core purpose front-loaded. The trailing 'GET /estimates' is mildly redundant but economically conveys the underlying call.

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 fully documented parameters and no output schema, the description supplies the return-field inventory and status vocabulary an agent needs to interpret results. Pagination semantics live in the schema, so nothing critical is missing.

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% across all 9 parameters (page, sort, filter, metadata, date bounds, customer_id), so the schema already carries parameter meaning. The description adds no syntax or format detail about those parameters, so the 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?

Clear verb+resource (list estimates) with an inline gloss that these are quotes, plus an enumeration of the returned fields (customer, status, expiration, deposit, totals, resulting invoice). It does not explicitly contrast with the sibling invoiced_get_estimate for single-record reads, so it stops short of a 5.

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?

The list nature makes the basic use case obvious, but there is no explicit when-to-use guidance, no mention of paginating via next_page, and no pointer to invoiced_get_estimate when a single estimate is wanted. Usage is implied rather than stated.

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