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

With no annotations, the description carries the full burden and does so well: it discloses that this is a REAL on-chain broadcast (a side effect, not a pure read), that it is free and unauthenticated, and that there is a rate limit of one broadcast per 5-minute window capped daily. It also enumerates the returned artifacts and the explicit limits of what is proven.

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 description is effectively front-loaded with the [FREE] tag and purpose sentence, then mechanics, returns, caveats, and a param note. It is slightly long with a few evocative phrases ('proving the exact rails a real sportsbook bet travels right now'), but nearly every sentence carries actionable information.

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?

Given an output schema exists, the description need not restate return values, yet it additionally covers side effects, authentication, rate limits, parameter meaning, and the boundaries of the proof. An agent has everything needed to decide whether and how to invoke it.

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 0% and the schema gives only bare strings with empty defaults, so the description must compensate and largely does: it labels 'league' and 'team' as optional context labels and supplies examples ('nfl', 'packers'). It could clarify how these labels affect the output, but the meaning is far clearer than the raw schema.

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 and resource (prove the sports-bet x402 payment rail is live) and then defines precisely what 'proof' means: a zero-value shadow settlement on Base with an EIP-712 transferWithAuthorization signed, recovered, and broadcast on-chain. This distinguishes it concretely from siblings such as check_facilitator_liveness, get_sportsbook_status, and get_sports_payment_telemetry.

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 clear usage context ('before risking a real bet') and a scoping exclusion ('Does NOT prove your own wallet balance or allowance; real bets still need real USDC'). It does not explicitly name alternative tools the agent should consider, but the when-to-use condition is unambiguous.

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