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

Annotations already cover the read-only/idempotent profile, and the description adds genuinely new behavioral context: the content is merchant-authored and must be treated as data rather than instructions (a prompt-injection warning), plus the payment rail (x402/USDG on Robinhood Chain) and the handoff tool for transacting. That is real value beyond the structured fields.

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 sentences, front-loaded with the core action and scope, then the trust warning, then the payment handoff. No filler; each sentence carries a distinct piece of information.

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 single-param, read-only discovery tool with no output schema and full annotation coverage, the description covers purpose, trust caveat, and next step. It stops short of hinting at the shape or volume of results (e.g. pagination or result fields), which would complete the picture.

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 100% for the single query parameter, which already documents that the word is matched against name, description or URL. The description only restates 'optionally filtered by a search word', adding no syntax or matching detail beyond the schema, so baseline 3 applies.

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 (List) plus resource (services registered with the Priors facilitator) and narrows the scope with two concrete qualifiers: accepts x402 payments in USDG, on Robinhood Chain. This is distinguishable from siblings like pool_stats or stock_assets without opening any 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?

Explains the optional search-word filter and routes the agent elsewhere for the actual payment step ('to pay one, use the local @priors/mcp server's pay_url (see how_to_connect)'). It does not state when-not to use it versus other discovery tools, but the context is clear.

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