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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds valuable context beyond that: it validates using the same parser and renderer as a save and reports what is wrong, clarifying that it mirrors real save behavior without mutating.

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 compact sentences that front-load the core behavior and end with the key non-mutating guarantee. No wasted words.

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 simple single-parameter validation tool with no output schema, the description is largely complete: it explains what is checked and that nothing changes. It could be slightly richer by hinting at the return shape (e.g., list of errors vs. a boolean), but annotations already carry the safety profile.

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 coverage is 100%, so the single 'doc' parameter is already documented in the schema as 'A paywall document (version: 1)'. The description adds no further parameter-level detail, which is acceptable given the high coverage baseline.

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 (validate) and resource (paywall document) with precise mechanics: it runs the document through the same parser and renderer a save uses. This clearly distinguishes it from save_paywall_doc and validate_onboarding_doc.

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?

Implies usage before saving by saying it uses the same parser and renderer a save does, and 'Changes nothing' signals it is a safe pre-check. However, it does not explicitly name save_paywall_doc or say when not to use it, leaving the alternative selection slightly implicit.

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