Price history

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

With no annotations, the description must carry behavioral disclosure, and it does: it states data is stored rather than fetched, defines ordering, lists returned fields, includes min/max, and mentions the free 30-observation limit. It could add what happens when both id and url are omitted, but the disclosed behavior is substantial.

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?

Three short sentences, all information-bearing, with the primary purpose front-loaded. There is no repetition of schema field names or filler text.

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 simple read-only history tool with no output schema, the description covers return content, ordering, storage behavior, and free-tier limits. Minor gaps remain around parameter selection (id vs. url) and exact limit behavior, but overall the agent has enough to call it correctly.

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%, so the baseline is 3. The description adds minor context beyond the schema, such as implying id/url identify one watch and clarifying the free 30-observation limit, but it does not substantially enrich parameter meaning.

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 clearly states the tool lists one watch's stored observations with a specific ordering (oldest to newest) and enumerates the returned fields (price, currency, source, confidence, min, max). It also distinguishes itself from current-price fetching tools by explicitly saying 'Nothing is fetched.'

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 gives clear context for when to call it ('to list one watch's stored observations') and notes a free-tier behavior. It does not explicitly name alternative tools or state when not to use them, but the context is unambiguous enough for an agent to route correctly.

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