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

Beyond the readOnly/idempotent annotations, it explains that changes are counted only between consecutive scans, that series cuts (comparableSince) suppress moves, and that unknown slugs return found:false rather than a fabricated series. This is significant behavioral disclosure, though the clause describing comparableSince cuts is syntactically garbled and harder to parse than it should be.

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?

The core purpose is front-loaded, but the middle sentence about comparableSince is dense and grammatically tangled, forcing re-reading. Some of the enumerated stats could be trimmed since they do not affect invocation.

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 no output schema, the description usefully enumerates the returned stats and the found:false miss case, and annotations already cover the safety profile. The only gap is that the series-cut logic, which materially affects what the stats mean, is communicated unclearly.

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 kind enum and slug format are already documented in the input schema. The description reinforces that the tool operates on ONE entity and that slugs resolve across both kinds, but adds little beyond the schema's own notes.

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 and resource — the full dated price series for one product or vendor by slug — and enumerates the derived stats it returns. It is clearly distinguishable from siblings such as compare, price_movers, and get_normalized_pricing, which deal with comparisons and aggregate movement rather than a single entity's series.

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?

Gives concrete usage contexts: 'how much did X cost', 'did X's price drop', and price-trend questions. It does not explicitly name a sibling as the alternative or state when not to use it, so the routing guidance is clear but not exhaustive.

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