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

The annotations say readOnlyHint=false, which would be surprising for a 'get' tool, and the description resolves it: calling it reads the store when there is no snapshot for today and adds it to the daily snapshot list. It also discloses idempotency-relevant behavior and the ambiguous-candidate return mode, adding real value beyond the annotation flags.

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?

It is a dense, front-loaded paragraph where nearly every sentence earns its place (precondition, side effect, param matching, return shape, ambiguity handling, exclusions). The return-shape sentence is mildly redundant given an output schema exists, but nothing is padding.

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 two-param read tool with an output schema, the description covers everything an agent needs: prerequisite state, side effect of calling, argument forms, ambiguity handling, and sibling routing. Return values are also summarized even though the output schema carries them, so nothing 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 coverage is 100% and both parameters are fully described there, so the baseline is 3. The description's note that 'an exact handle or title wins over part of a title' and that several partial matches come back as candidates largely restates what the schema already documents for `product`, adding little new syntax or format guidance.

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 description states a specific verb+resource (read one product's price and availability movement over tracked days) and explicitly carves out the two sibling tools it is not: check_store_prices for whole-store changes and compare_store_prices for cross-store comparison. An agent can distinguish it from every sibling without opening a schema.

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?

It gives concrete example questions, states the precondition (most useful after check_store_prices has tracked the store, since history starts at the first snapshot), and names explicit exclusions with the alternatives to use instead. The ambiguous-status path is also spelled out: ask the user to pick a candidate, then re-call with that title.

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