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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely non-derivable behavioral context: results are scoped to the latest completed daily refresh and missing records must not be treated as cancellations. It stops short of describing pagination, ordering or refresh-staleness behaviour.

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 tight sentences with no filler: scope first, then the critical interpretation caveat. Front-loaded and every sentence carries weight, though the phrasing 'Read changes' is slightly clipped for a standalone opening.

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 and no parameters, the description carries the full burden of explaining the return, and it only partially does so – it establishes the refresh window and the cancellation rule but not what a 'change' contains (added vs modified vs withdrawn) or whether ordering/timestamps are provided. Adequate for a param-less read, but an agent cannot fully anticipate the payload.

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?

The tool takes zero parameters, so there is no parameter semantics for the description to add; the baseline for a param-less tool is 4. Nothing in the text misdescribes or distorts the empty schema.

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 ('Read changes') and a scope ('latest completed daily refresh'), which distinguishes it from get_tender, search_tenders and get_operator_offer as the delta/changefeed tool. It falls short of a 5 only because the resource being changed (tenders) is never 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?

Usage is implied rather than stated – an agent can infer it is for retrieving incremental updates after the last refresh, but no alternative (e.g. search_tenders or get_tender for full state) is named and no when-not condition is given. The 'absence is not cancellation' rule is interpretive guidance but not selection guidance.

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