market_invoke_tool

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

No annotations are provided, so the description carries the full behavioral burden and does so well: it discloses the trial quota per installation, that exhaustion returns 402 and is reported rather than faked, and that results come with a hub-signed receipt nonce verifiable against the published key. It does not disclose possible side effects of the invoked capability, which is the remaining gap.

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?

Four sentences, front-loaded with the core action, and every sentence earns its place: trial tier, verifiability, quota/402 behavior, paid-access exclusion. No filler or repetition of the schema.

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 an output schema present, return values need not be spelled out, and the description covers the operational essentials an agent needs (quota limits, error semantics, verifiability, paid-path exclusion) alongside fully documented parameters.

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 parameters (including the non-obvious product_id and source_hub federation caveats) are already documented. The description adds no parameter-level guidance beyond the schema, so the baseline of 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?

States a specific verb+resource with scope: 'Run one capability from market_search on the hub's free trial tier.' It explicitly grounds the tool against the sibling market_search_tool (this invokes what that one discovers), so an agent can distinguish them without opening schemas.

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?

Clear context: use after market_search, on the free trial tier, and a when-not (paid access requires on-chain escrow, deliberately unavailable here). It does not name an alternative tool to use for paid access, but the trial/no-trial boundary is well stated.

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