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

Annotations already declare readOnly=false, destructive=false, openWorld=true, so the safety profile is partly covered. The description adds genuine behavioral context beyond that: nothing is sent to the client, the API key requirement, the deposit display behavior, and the past-date constraint on expiry.

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 core points are front-loaded, but the same idea is stated three times ('Nothing is sent to the client', 'Nothing is sent: the client sees it only after send_document', 'It reaches no one'). That repetition wastes space that could carry parameter or return detail.

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 7-parameter creation tool with no output schema, the description covers the key semantics: it creates and saves, sends nothing, and honors deposit/expiry rules. Return values needn't be explained without an output schema, so the coverage is nearly sufficient, with minor room for detail on line items or discount 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, but the description adds meaning for at least two parameters: deposit ('a percent or an amount ... shows under the total as Deposit Due') and expires_on ('cannot be in the past'). This goes beyond the raw schema text.

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 and resource ('Creates and saves an estimate for a client') and names the scope fields (line items, optional deposit and expiry). It explicitly distinguishes itself from the sibling send_document by clarifying the estimate is unsent until then, so an agent can route correctly.

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?

Names the alternative workflow (the client sees it only after send_document) and gives the condition that selects this tool over that one. It also flags that it 'runs without asking,' implying no confirmation step. It stops short of an explicit when-not/alternative statement, but the routing context is clear.

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