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

Annotations already cover read-only and idempotency, but the description adds genuinely useful traits: deterministic output, pure function with no external calls or ML, and hashing over the exact input bytes. The only tension is openWorldHint=true versus "no external calls," though this reads as a permissive default rather than a real conflict.

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?

Two dense sentences with no filler, front-loaded with the digest components and closing with the determinism guarantee. Every clause carries 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?

The tool is simple, the single parameter is fully documented, and an output schema exists, so return detail is a bonus rather than a requirement. The one gap is the absence of any indication of when an agent should reach for this tool, which for a one-param utility is the only missing piece.

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 100% and the single parameter's description already states the text is arbitrary and hashed exactly as given, so the schema does the heavy lifting. The description clarifies the digest's components but adds nothing new about the parameter itself, matching the baseline 3 for fully covered schemas.

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 concrete verb+resource ("text digest") and enumerates the exact outputs: word count, top-5 frequent words with stop words excluded, first sentence, keccak-256 hash. No sibling tool performs text analysis, so the purpose is unambiguous without opening the 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?

No when-to-use or when-not-to-use guidance is given; nothing routes the agent among the finance/validation siblings or explains the intended scenario (e.g. deduping scraped text before downstream processing). "Pure function — no external calls" is a property, not usage guidance.

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