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

With no annotations, the description carries the burden of explaining behavior. It does state the core behavior (explain code) and the nature of the result (plain English), which is non-mutating and fairly clear. However, it does not mention return format, limitations, or the role of the 'lang' parameter.

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 one short sentence with the core action front-loaded. The 'AI Code Explain' label is somewhat redundant, but there is no wasted explanatory prose. It is compact though it sacrifices useful clarification.

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 tool with two parameters, no annotations, no output schema, and close siblings, this description is incomplete. It does not clarify what 'lang' means, what the output looks like, which parameters are needed, or how this differs from adjacent code-analysis tools. An agent would have to guess or inspect elsewhere.

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%, so the baseline of 3 applies even though the description adds no parameter-level detail. The description adds nothing beyond the schema, and the schema's 'Lang to process' is ambiguous, but the high coverage prevents a lower score.

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 action ('Explain code') and the resource ('code'), and even specifies the output style ('plain English'). The purpose is immediately understandable and distinct from review or diagnostic tools, though it does not explicitly name any sibling alternatives.

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 guidance is given about when to use this tool versus x402-ai-code-review, x402-code-diagnose, x402-sql-explain, x402-regex-explain, or other related tools. There are no exclusions, prerequisites, or contextual hints beyond the basic 'explain code with AI' statement.

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