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

With no annotations at all, the description carries the full behavioral burden. It does disclose the paid model ('$0.002 USDC/call, x402, eip155:8453'), which is genuinely useful, but it never states that the operation is side-effect free, how failures (unsupported algo, oversized input) are reported, or the default algorithm when 'algo' is omitted.

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?

One dense sentence with no wasted clauses; the payment metadata is bracketed up front and the functional statement follows immediately. It is slightly cramped, mixing billing metadata with the operation description, but nothing is redundant.

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 two-parameter utility with no output schema, the description covers the operation, algorithm set, return shape and cost, which is close to sufficient. The missing default-algorithm behavior and encoding assumption are the notable gaps an agent could trip over.

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 both parameters are documented there, so the baseline is 3. The description repeats the algorithm list and characterizes the input as 'arbitrary string' but adds nothing about the default when 'algo' is not supplied or about text encoding.

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 ('Hash') and resource ('an arbitrary string'), enumerates the five supported algorithms, and names the return value ('hex digest with input byte length'). This clearly distinguishes it from unrelated siblings like util_uuid, util_time and util_ping.

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?

Usage is only implied by the operation itself; there is no explicit when-to-use statement, no mention of when not to use it, and no alternative sibling called out. For a self-evident hashing utility that is adequate, but the agent gets no routing guidance beyond the verb.

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