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

With no annotations, the description carries the burden, and it does disclose key traits: the tool is free, involves no x402 payment challenge, and content is version-pinned and reproducible via a SHA-256 corpus identity. However, it never says what form the response takes (text document vs. JSON), its size, or whether the criteria can change across revisions - gaps that matter for a zero-parameter document fetch.

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?

Front-loaded with the core identity and pinning, then the content inventory, then the free-access note and HTTP equivalent. The middle clause is a long dash-separated inventory that borders on exhaustive, but each item is genuinely informative for an agent deciding whether to read it. Slightly dense phrasing keeps it from a 5.

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 zero-parameter, no-output-schema documentation tool, the description is close to complete: it identifies the version, the exact artifact contents, reproducibility guarantees, and cost. The only thing an agent might want that is missing is the response format and approximate length.

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 the baseline is 4; there is nothing for the description to compensate for. The schema coverage is 100% and empty, consistent with the description's claim that it is called directly with no inputs.

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 and version: the published criteria for the MCP Auth-Surface Conformance service (mcp-auth-surface/v1), pinned to revision 2026-07-28, and enumerates its contents (38 graded checks, grade vocabulary, not-assessable disclosure, corpus hash). An agent can tell this is the spec/documentation tool rather than a running check. It does not explicitly name the sibling tools (auth_surface_check, auth_surface_precheck) it complements, so differentiation is inferred from 'criteria' rather than stated.

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 - every report is reproducible from them' gives a clear when-to-use: consult this prior to requesting a paid report. It also states no payment/x402 is required and gives the HTTPS equivalent. It stops short of naming the paid sibling or stating when this is unnecessary (e.g., if you already know the check definitions).

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