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

With no annotations provided, the description carries the behavioral burden. It discloses the core action (releasing escrow and paying), the cost implications ('Free for the buyer; Sphere's commission is taken from the contractor's payout'), and authentication needs. It does not mention irreversibility or return behavior, but the main behavioral and financial consequences are 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 sentences with no wasted words. The primary action is front-loaded, followed by cost and authentication details. Every sentence earns its place.

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 simple 3-string-parameter action with no output schema, the description covers the essential context: trigger, financial effects, and required credentials. It does not describe the return value or post-completion state, but the essential calling context is present. A slightly stronger warning about irreversibility would make it fully 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?

The schema has 0% description coverage, so the description must compensate. It names all three required parameters and adds useful provenance for api_key ('from marketplace_register'). However, it only lists agent_id and contract_id without further explanation, relying on self-evident names rather than fully defining their semantics.

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 uses a specific verb and resource: 'Release the escrow and pay the contractor once you accept the delivered result.' This clearly states the tool's function and differentiates it from siblings like marketplace_accept_contract or marketplace_deliver_contract by focusing on final payment after acceptance.

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?

It provides a clear condition for when to use the tool: 'once you accept the delivered result.' This implies the correct workflow position after delivery and acceptance. It does not explicitly name alternatives or exclusions, but the trigger is specific enough for an agent to select it appropriately among siblings.

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