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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds a genuinely useful behavioral fact beyond the schema/annotations: the call 'Counts as 5 searches against the account's Marketplace limit,' a quota-cost disclosure that steers call frequency. It does not discuss auth or return format, but the safety profile is already annotated.

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, zero waste: the first front-loads purpose and return contents, the second delivers the quota cost and the usage constraint. Every clause 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 read-only detail tool with no output schema and full schema coverage, the description covers what it returns, where the id comes from, and the cost of calling it. Nothing an agent needs to invoke it correctly is missing.

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%, so all four parameters (including the elaborate context and conversation_id guidance) are fully documented in the schema. The description only reinforces that id comes from search_public_listings, adding marginal meaning. Baseline 3 is appropriate when the schema does the heavy lifting.

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 (Get), resource (one Marketplace listing by id), and precisely enumerates what it returns: the listing broker's name, brokerage, phone and email. It also names search_public_listings as the sibling that produces the id, so an agent can distinguish this detail-fetch from the search step.

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?

Explicit routing and condition: the id comes from search_public_listings, and it should be called 'only for listings the user wants to contact about.' That is a clear when-to-use rule tied to a concrete user intent, leaving little to inference.

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