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

With no annotations, the description carries the full burden and delivers meaningful context: the escrow lifecycle (buyer funds directly, you deliver, buyer approves), that disputes route to Jev-advised arbitration, and a 2% platform fee on release. It does not state permission/auth requirements or rate limits, but the escrow and fee disclosure is substantial behavioral context beyond the schema.

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 dense sentences with no filler. The core action and the escrow/fee consequences are front-loaded, and every clause (returns order + escrow address, fee) 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 mutation tool with no annotations and no output schema, the description covers the return value ('the order plus its on-chain escrow address'), the post-listing flow, and the fee. It stops short of auth/prerequisite detail, but an agent has enough to call it correctly.

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 71%, so most parameters are documented in the schema itself. The description only loosely maps to parameters via 'fixed price' (priceSats) and 'digital or physical item' (fulfillment), adding no new syntax or format detail. Baseline 3 is appropriate when the schema does most of the work.

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: 'List a digital good or physical item at a fixed price,' which tells the agent this creates a market listing/order. It is clear on its own but does not explicitly differentiate itself from siblings like market_list, market_get, or list_services, leaving the agent to infer the distinction from the name.

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 — the agent can infer this is the tool for putting an item up for sale — but there is no explicit when-to-use guidance and no mention of alternatives (e.g., market_list for browsing, market_get for retrieval). The agent must map the verb to intent unaided.

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