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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), so the bar is lower, and the description still adds real context: a hard cost of $0.03 USDC, a 25-result cap, and the fact that empty or invalid queries are refused before charging. It does not mention whether repeat identical calls are billed again, which is the one behavioral gap left given idempotentHint=true.

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?

Two sentences, front-loaded with price and then payload contents, with the payment-refusal rule last. Dense but every clause carries information. Slightly long within a single clause, but 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?

With no output schema, the description correctly enumerates the returned fields (incumbent, value, extensions, re-procurement window, official notice links) and states the 25-record cap, which is what an agent needs to judge fitness. Payment mechanics are covered by both the description and the x402_payment schema entry. Only the billing-on-repeat behavior is unaddressed.

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%, so the schema already documents all seven parameters including the enums, the 1-24 month bound and the x402 payment payload. The description only loosely echoes the window/incumbent concepts without adding format or constraint detail. Baseline 3 is appropriate when the schema does the heavy lifting.

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 names a specific resource and scope: up to 25 published edtech contracts at English schools/trusts/councils ending within a window, plus the fields returned (incumbent, value, extensions, re-procurement window, notice links). That is enough for an agent to distinguish it from school_signals_search or school_buyer_brief in practice. It never explicitly contrasts itself with those siblings, 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?

Usage is implied rather than stated: the tool is for finding upcoming renewals, and the schema's buyer param points back to school_signals_search, hinting at a workflow. There is no explicit when-to-use vs. the other school_* siblings or when-not-to-use guidance. The payment precondition ('empty results and invalid filters are refused before payment') is the only concrete gating rule.

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