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

Annotations already cover readOnly, idempotent, non-destructive, but the description adds substantive context the annotations cannot: the quote reports balance sufficiency, today's limit, and the owner's ask-first amount. "Charges nothing" reinforces the safety profile in economic terms.

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 short sentences, front-loaded with the core definition, then the parameter instruction, then the no-charge note. 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?

The description names what the quote returns (price, balance fit, limit, ask-first) so the missing output schema is tolerable, and it explains how to frame the nested arguments payload. It stops short of describing error conditions, such as an unknown tool name or invalid arguments.

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% and the schema already documents both `tool` and `arguments` with examples. The description's "Pass the tool's name and the arguments you would call it with" restates the schema rather than adding syntax, validity rules, or failure behavior.

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?

The description states a specific resource (the exact credit price of a job) and a specific operation (quoting it before execution), with a clear scope that separates it from buy_credits and get_job. An agent can immediately tell this is a dry-run cost estimator rather than an executor.

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?

"before making it" gives an explicit call-ordering rule, which is the key usage signal for a pre-flight estimator. No explicit exclusion or named alternative is given, but the guidance is unambiguous in practice.

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