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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds the non-obvious cost signal ('Free'), which is genuine behavioral context not in the annotations, but says nothing about batching limits, per-item error handling, or unknown-name behavior. With annotations carrying safety, a 3 is appropriate.

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 tight sentences with zero filler; the action is front-loaded and the category enumeration is the most information-dense part of the definition. Nothing could be removed without losing meaning.

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 one-parameter, no-output-schema reader, the description covers input intent and the set of possible classification results, which effectively conveys the return vocabulary. It does not state whether one label comes back per input algorithm or an aggregate is returned, a minor remaining gap.

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%: the single 'algorithms' array parameter is documented with format hints and examples ('RSA-2048', 'ECDHE-RSA-AES256-GCM', 'X25519MLKEM768'). The description lists output classes rather than adding input-format meaning, so baseline 3 is correct when the schema does the heavy lifting.

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 ('Classify') and resource ('cryptographic algorithms') and enumerates the exact output categories (quantum-vulnerable, post-quantum, hybrid, symmetric/hash, unknown) with representative algorithms. There is no overlapping sibling, so an agent can unambiguously identify what this tool does.

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 guidance, no prerequisites, and no named alternatives. The only directive-style statement is 'Free,' which is a cost note rather than usage context. The agent must infer from the purpose alone that this is the right tool for qualifying algorithm names.

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