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

Annotations only declare the read/write/destructive profile; the description adds the important behavior that nothing is client-visible until send_estimate, that it only saves a draft, and that it can run without confirmation. It also states the API-key requirement. These are genuine additions beyond the annotations, though it says nothing about idempotency or validation failures.

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 with the core purpose and scoped nicely, but the client-visibility point is stated twice ('Nothing goes to the client until you send it' and 'The client sees nothing until send_estimate'), which is mild redundancy in an otherwise tight paragraph.

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 draft-creation tool with no output schema, the description covers what is created, the total math, the client-visibility semantics, and the auth requirement. It is adequate to invoke correctly, with only minor gaps (no mention of what a returned draft looks like or validation behavior).

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 baseline is 3. The description goes further by defining how a line total is computed (quantity x unit cost + markup) and how the estimate total derives from the lines, which adds meaning about the items parameter beyond its schema description.

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?

Specific verb (draft/create) plus resource (estimate) with the scope stated: it saves a draft estimate on the project. It also distinguishes itself from the sibling send_estimate, so an agent can tell the two apart 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?

Clearly frames the tool as the pre-send drafting step and names the alternative ('Nothing goes to the client until you send it... until send_estimate'), giving a usable when-to-use signal. It stops short of explicit when-not guidance or prerequisites beyond the API key note.

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