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

With no annotations, the description carries the full burden. It discloses that the file itself is not transmitted, that admissibility is a court determination, and that unauthenticated calls are rejected. This adds valuable behavioral context beyond the schema, though it does not detail the affidavit's structure 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 description is three sentences with no filler: it front-loads the purpose, then explains key behavior, then provides auth requirements and a legal disclaimer. Every sentence earns its place.

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 moderate-complexity tool with no output schema or annotations, the description covers purpose, file transmission behavior, legal caveat, and authentication. It does not specify the return structure of the affidavit, which would improve completeness, but overall it is well-rounded.

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 100% for all four parameters, so the schema already documents them. The description adds minor context by stating 'only the digest + filename + size + MIME type are anchored' and that the caller computes the hash, but this does not significantly enhance parameter understanding beyond the 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 clearly states the specific verb+resource: 'Anchor a SHA-256 file digest to Knox and return an affidavit architected for FRE 902(13)/(14) self-authentication.' This distinguishes it from sibling tools like anchor_event and anchor_mcp_tool_call by explicitly targeting file digests.

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 provides clear context for use: caller computes the hash and only metadata is sent, which indicates when this tool is appropriate. It also states the prerequisite requiring a Bearer API key, but does not explicitly mention exclusions or alternative tools, so it stops short of the top score.

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