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

The annotations are sparse (only non-read-only, non-idempotent, non-destructive), and the description carries the full behavioral burden. It discloses the refusal condition, bond implications, good-till-cancelled default, and hash-chain recording, all of which go well beyond the structured annotations.

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 dense sentences front-load the actor and allowed state, then explain the refusal condition and side effect. Every sentence contributes a necessary fact with 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 mutating tool with an output schema and sparse annotations, the description covers prerequisites, the clearing alternative, the failure condition, and the persistent side effect on the hash chain. An agent has enough information to decide when to call it and what to expect.

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 schema already documents both listing_id and deadline, including ISO 8601 format, future requirement, and null/omitted semantics. The description adds context about good-till-cancelled as the platform default, but it largely restates the parameter meanings already present in the 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 ('set or clear') applied to a listing's closing time, and identifies the actor ('poster') and the required listing state ('OPEN', no sealed proposals pending). This clearly distinguishes it from sibling operations like market_post_listing or market_award.

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?

Explicitly states when the tool is usable: only for the poster of an OPEN listing before sealed proposals exist. It also gives a clear when-not condition—once sealed proposals exist, the change is refused until they are decided or withdrawn—though it does not name alternative sibling tools.

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