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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds genuinely new context: the listing is 'normalized across Alt's own native listings and its aggregated external listings,' explaining the data provenance. It stops short of richer traits (e.g. freshness or availability of external data), and an output schema already covers the return shape.

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 the purpose front-loaded and the input-provenance note second. No filler or redundancy; 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 an output schema and safety annotations already in place, the description covers purpose and data provenance adequately. It is slightly incomplete on sibling routing (alt_asset vs alt_sold_listings), but nothing essential for correct invocation 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 both parameters are already documented in detail, including the sold-listings listing_id variant. The description only slightly reinforces this by stating where id and listing_type originate, adding little beyond the schema, so the 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+resource: it fetches 'One Alt listing's full public detail' and clarifies it is normalized across native and aggregated external listings. This distinguishes it from the search-style siblings (alt_search, alt_auctions), though it never names those siblings explicitly to draw the routing contrast.

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?

The description establishes the prerequisite workflow by noting 'id and listing_type come from a prior alt_search/alt_auctions result,' which implies this is the detail-fetch follow-up. However, it gives no when-not guidance and never contrasts with plausible alternatives like alt_asset or alt_sold_listings (a completed-sale path the schema hints at).

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