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

The description states the operation is deterministic and that 'no network request or external provider is used', but the annotations declare openWorldHint=true and idempotentHint=false. A pure, deterministic local hash is by definition idempotent and closed-world, so the declarations conflict with the stated behaviour. This is an annotation contradiction.

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 core capability is front-loaded, followed by constraints, the interpretation caveat, and finally pricing — a sensible order with little waste. It is dense but not padded; only the pricing sentence could be considered non-essential.

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?

With no output schema, the description correctly compensates by specifying the return format (hex plus Base64), plus the input bound, determinism, and the cost model. The one meaningful gap is the missing default algorithm for an optional parameter, and no error behaviour is described.

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 enum already enumerates sha256/sha512, so the schema carries the parameter burden and baseline 3 applies. The description usefully confirms the 100 KiB bound and names both algorithms, but adds no syntax or default-value guidance (notably the algorithm parameter is optional yet no default is given).

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 verb (hash), the resource (caller-supplied UTF-8 text), the two supported algorithms, and the exact output shape (hexadecimal and Base64 digests). That is enough for an agent to separate it from the encoding sibling text_base64 without opening any 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?

It supplies one real usage boundary — digests are not proof of authenticity or password security — which tells the agent when the result should not be relied on. However, there is no explicit routing versus siblings such as text_base64, and no statement of prerequisites beyond the price. Usage is implied rather than prescribed.

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