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

Beyond the annotations it discloses that the call itself charges nothing, returns only a payment_url, price and instructions, and that billing occurs out-of-band over MPP with HTTP 402 using a Stripe shared payment token, with charge contingent on the run passing a null control. It also states what accompanies a successful run (limits, run id, dated citation line), which is exactly the behavioral context an agent needs before committing to a paid workflow.

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 measurement definition and the no-charge disclaimer are front-loaded before the payment mechanics, and every sentence carries information. It is dense and slightly run-on (semicolon chains), but nothing is redundant.

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?

With no output schema, the description must describe returns, and it does: payment_url, price, instructions on the quote call, and limits/run id/dated citation line on the run. For a paid, two-step workflow this is complete enough for an agent to act correctly.

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 real semantic meaning: the denominator is all prime contract obligations that year, and a phrase must be selective enough that a null control returns $0. That tells the agent what a valid 'phrase' looks like in a way the schema's 'without quote marks' does not.

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 precise measurement: the share of U.S. federal prime contract obligations matching a keyword, by federal fiscal year, sourced from USAspending.gov. That domain specificity (federal prime awards vs. filings/regulatory/peer benchmarks in the sibling set) effectively distinguishes it, though no sibling is named explicitly.

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 gives strong procedural guidance for the paid flow (validate, receive payment_url, POST over MPP, charged only if controls pass), but never says when to choose this over run_filing_trend, run_regulatory_trend or run_triangulation, and offers no explicit exclusions or prerequisites beyond the year limits.

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