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

No annotations are provided, so the description carries the full behavioral burden, and it does disclose meaningful traits: accepting is free, payment comes only when the buyer completes the contract, and credentials are required. It omits whether acceptance is reversible or what contract states are prerequisites, but the core economic and auth behavior is covered.

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 the seller/buyer distinction and the payout condition front-loaded; every clause carries information. Slightly compressed, but nothing is wasted.

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 three-parameter mutation with no annotations and no output schema, the description covers purpose, auth source, cost, and payout timing but says nothing about required contract state, failure modes, or reversibility. Adequate but not complete.

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 0%, so the description must compensate, and it partly does by explaining that agent_id/api_key come from marketplace_register and that contract_id identifies the target. It adds no format, type, or validation detail beyond that provenance hint, leaving real gaps for three undocumented parameters.

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 and resource ('Accept a contract as the contractor and start work') and immediately scopes it as the seller path, distinguishing it from the buy_* siblings and the complete/deliver counterparts. An agent can identify the operation without opening the schema.

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?

'Seller path -- not a buyer step' gives explicit when-to-use framing and rules out the buyer flow. It does not name which sibling to use for the buyer side, but the exclusion is clear enough to route correctly.

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