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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds genuine context beyond that: it discloses that data is normalized across Alt's own listings and aggregated external sources, which tells the agent about provenance and mixed-source data quality. It does not mention auth or rate limits.

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 tight sentences with no filler; the resource identity and the normalization scope are front-loaded, followed by the parameter-provenance constraint.

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 an output schema present, return values need not be explained, and annotations cover the read-only/open-world profile. Purpose, parameter provenance, and data-composition context are all covered; only explicit sibling routing is absent.

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 coverage is 100% and both parameters are already documented in the schema, including the enum-like listing_type values and their meaning. The description's note that they come from a prior search result is largely redundant with the schema text, so baseline 3 is appropriate.

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 resource (one Alt listing) and what is returned (full public detail), and clarifies that results are normalized across native and aggregated external listings, which differentiates it from alt_search/alt_auctions list tools. It does not name sibling detail tools explicitly, so it lands just short of a 5.

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?

Explicitly states that id and listing_type must come from a prior alt_search/alt_auctions result, which gives the agent clear sequencing context. It does not state when not to use it or name alternative detail-fetch tools, so no exclusions are provided.

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