get_rival_market

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

Annotations already establish read-only, idempotent, non-destructive and closed-world behavior, so the bar is lower. The description adds two genuinely non-obvious traits: data is measured on request and cached for 7 days, and install deltas only exist once two measurements have accumulated. That materially affects what an agent should expect back.

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?

One dense sentence with a trailing caching clause; the core resource leads and platform detail follows, so it is front-loaded and has no filler. The semicolon-chained clause is heavy but each clause carries distinct information about a different platform.

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 carries the return-value burden and largely discharges it by naming the exact fields per platform plus the caching window. Minor gaps remain (behavior when the rival is absent from the chosen storefront, whether price range is a single value or interval) but nothing an agent needs to invoke it correctly 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 all four parameters (appId, rivalId, country, platform) are already documented inline, including defaults and the enum. The description's platform-specific narrative reinforces the platform parameter's meaning but adds no syntax or formatting detail beyond the schema, so 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 description names the resource (a rival's market data for one storefront) and enumerates exactly which metrics each platform returns, so the agent knows precisely what the tool produces. It does not, however, differentiate itself from near neighbours like get_rival_detail or get_rivals, which is the only thing keeping it from a 5.

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?

Usage is only implied: an agent can infer 'use this to get a rival's storefront metrics' but there is no statement of when this beats get_rival_detail, nor any prerequisite beyond the schema's reference to get_rivals/list_apps. The 'kept for 7 days' note hints at freshness tradeoffs but never spells them out as guidance.

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