check_facilitator_liveness

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

With no annotations supplied, the description carries the full behavioral burden and does deliver real value: it declares the call free, moves no funds, is a single round-trip, and defines staleness thresholds. However, the text is truncated mid-sentence at 'Verify the server signature recove', cutting off the critical verification step of the signed flow, and it never says whether nonces are single-use or whether the signed path has any cost or side effects.

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 '[FREE]' tag plus a one-line summary is a strong front-load, and the numbered two-level structure is easy to scan. The EIP-712 parenthetical is dense enough that the description overruns and is cut off mid-word, which is a sizing and completeness problem rather than tight writing.

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 3-parameter, zero-annotation, no-output-schema tool, the description does cover both return shapes (heartbeat stats window vs server-signed block number) and the cost model. But the truncation leaves the signed-mode verification procedure unfinished, and nothing is said about failure modes or what a rejected signature returns, leaving a genuine gap for the higher-risk path.

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 0%, so the description has to explain all three parameters, and it largely does: signature is over an EIP-712 Ping template, with domain {name: x402-facilitator, version: 1, chainId: 8453} and types Ping of action/nonce/timestamp strings, and the caller must pass the same nonce and timestamp. That is meaningful added semantics well beyond the bare string types. It loses a point because the 'action' value and the empty-string default behaviour are never clarified.

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: checking whether the x402-agent-pay.com settlement pipeline is alive and current, with the cost/impact ('[FREE]', 'no funds moved') front-loaded. It does not name or contrast with near-neighbours such as facilitator_live_dashboard, get_settlement_pulse, or check_x402_endpoint, so an agent must infer the distinction from the resource name alone.

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 two operating levels (unsigned vs signed) and the interpretation thresholds (age <= 12s is live, > 30s treat as down) give useful decision context. However, there is no statement of when to pick this tool over the many sibling liveness/pulse tools, and no prerequisite guidance for the signed mode beyond the template itself.

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