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

Annotations already declare read-only, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new operational context: it is free, triggers no x402 payment challenge, and has an HTTP equivalent endpoint. The only gap is that it never says whether the criteria are stable/versioned over time, which matters for a spec-document tool.

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 payload list is front-loaded and the key ordering hint follows immediately, so the important information lands early. The no-payment note is stated three ways ("before paying", "no payment required: call directly without payment", "no x402 challenge; this tool is free"), which is redundant length for a tool that already reads as a free GET.

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?

There is no output schema, but the description compensates by listing the four components of the returned criteria, which is exactly what an agent needs to know before calling. With zero parameters and annotations covering the safety profile, nothing material is missing for correct invocation.

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?

The tool takes zero parameters, so there are no parameter semantics to explain and no risk of ambiguity. The description correctly implies a direct, unfiltered retrieval rather than a query.

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 a specific resource (published drift criteria for the MCP Manifest-Claim Audit extension, mcp-manifest-drift/v1) and enumerates exactly what it returns: digest canonicalisation rules, the signed digest block, the drift input contract, and comparison rules. That is materially distinct from manifest_drift (the actual report) and manifest_criteria (a different criteria set), so an agent can tell them apart without opening a schema.

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?

"Read these before paying for a drift report — every drift report is reproducible from them" gives a clear when-to-use condition and an ordering relative to the paid drift tool. It stops short of naming the sibling (manifest_drift) explicitly or stating when not to call it, which keeps it off a 5.

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