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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint=false, so safety is covered. The description adds genuinely non-structured context: the result ordering, the fact that only still-running contracts are returned, and the billing model (USD 0.01/call via x402 USDC on Base or an X-API-Key). Pagination/result-size behavior is not disclosed.

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 the scope and sort order an agent needs to route the call; the payment clause is verbose but conveys information an agent must know before calling. No filler or repetition.

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 read-only, no-output-schema query tool, the description covers scope, ordering, and cost, and annotations cover the safety profile. The remaining gap is pagination behavior for the `page` parameter and any hint about result shape, which is a minor omission rather than a blocker.

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 all four parameters (line, country, page, before) are already documented in the schema; baseline 3 applies. The description adds only the implicit "one line" framing, no format or filtering nuance beyond what the schema already says.

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 the resource (contracts of one line) and its exact scope (still running) plus the ordering (soonest end first), so an agent knows precisely what comes back. It stops short of explicitly naming a sibling (e.g. assay_line_contracts or assay_uncontested) that an agent might otherwise confuse it with.

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?

"the next tenders to come" implies the intent (finding upcoming renewal/tender opportunities), which is useful usage context. But there is no explicit when-to-use statement, no exclusions, and no named alternative for when the agent wants all contracts of a line rather than only still-running ones.

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