Data change probe

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 valuable behavioral context: the meaning of seq as a global change indicator, the existence of sub-counters, and the cost-effectiveness ('cheapest possible'). This goes beyond the structured annotations, though it doesn't discuss edge cases or rate limits.

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 three sentences, each earning its place: first states what it returns, second explains the decision rule, third provides context. No fluff or repetition.

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 no-parameter tool with an output schema, the description fully covers purpose, usage, and behavioral implications. It explains when to use (before re-listing) and what the return value indicates, making it complete for an agent to decide and invoke.

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?

The tool has zero parameters, so the baseline is 4. The schema coverage is trivially 100%, and the description doesn't need to explain parameters. It adds no additional parameter semantics but none are needed.

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 tool returns the global change counter (seq) plus sub-counters, with a specific verb ('returns') and resource ('change counter'). It also distinguishes itself from siblings like data_changes by positioning as 'the cheapest possible change check' and explaining its use for skip re-reading.

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?

Provides explicit when-to-use guidance: 'If seq hasn't moved since you last looked, NOTHING changed anywhere — skip re-reading' and 'Widgets use this for adaptive polling; you can too before re-listing a collection.' This tells the agent exactly the context for using this tool over alternatives.

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