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

Annotations already establish readOnlyHint=true, destructiveHint=false, openWorldHint=false, so safety is covered. The description adds real scope disclosure the annotations don't: which Market findings are returned here versus which require agent_open/place_open, and that the community entries carry their rules and drafted replies. No freshness, pagination, or permission details are given.

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?

The first clause front-loads the purpose and the return contents, then the routing sentence follows. The second sentence is dense with tool-name references ('agent_open, or place_open with market', 'discovery_read', 'set_aside') and unfamiliar terms like 'Marsell', which cost readability, but no sentence is filler.

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?

With no output schema, the description carries the burden of describing returns and does so by enumerating the four content types the tool surfaces. Combined with 100% schema coverage on the single optional parameter and annotations covering safety, an agent has everything needed to call it and interpret the result.

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?

Only one optional parameter and the schema already documents it at 100% coverage ('project id or exact name, optional when the account has one project'). The description echoes the notion of a project's buyers but adds no format or default behavior beyond what the schema states, 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 and resource ('Reads where a project's buyers are') and immediately enumerates the payload: communities with rules, live conversations with drafted replies, recurring questions, and rival prices. The second half explicitly separates it from agent_open/place_open, discovery_read, and set_aside, so an agent can route without opening schemas.

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?

Names alternatives and the condition that selects them: the rest of Market is 'what its agents found: agent_open, or place_open with market', the same findings plus buyer identity are 'discovery_read', and setting one aside is 'set_aside'. What's missing is an explicit statement of when NOT to call get_market (e.g., use discovery_read instead when buyer identity is needed), though the sibling mapping largely implies it.

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