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

Annotations already cover read-only, idempotent, non-destructive behavior. The description adds timing context (comps must have landed, ~20 sec delay), input provenance (scanId from a photo price), and the same-shape-as-price_item return promise, which are not in annotations.

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 pack the purpose, prerequisite, timing, and input source without extraneous text. The phrasing is slightly run-on, but 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 re-read tool with no output schema, the description supplies the essential call scenario and return shape via price_item reference. It doesn't cover failure states (e.g., calling before comps land) or the optional cost parameter, but those are partially covered by schema.

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 the schema fully documents scan_id and cost. The description reiterates the scan_id source but adds no new parameter meaning beyond the schema; 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?

The title provides a specific verb+resource ('Fetch a saved scan's result'), and the description elaborates on the exact resource: the finished result for a signed-in user's account. It distinguishes from siblings by tying the tool to the post-loading scan result and re-reading saved scans, which separates it from price_item and get_sold_comps.

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 states precisely when to call: with account.scanId after price_item reported comps still loading (~20 seconds later), or to re-read any saved scan. It does not explicitly name alternative tools or say 'do not use when...', so it lacks the when-not clarity of a 5.

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