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

With no annotations, the description carries the full burden. It discloses that 'No API key required' and describes the output (regimes with free/subscriber rule counts). It does not explicitly say 'read-only' but 'List' clearly implies a non-destructive operation, and the simplicity of the tool makes this sufficient.

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 two sentences, front-loaded with the verb and resource, and every phrase adds value (list, regimes, counts, no key, call first). There is zero redundancy or fluff.

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 zero-parameter discovery tool with no output schema, the description fully covers what it returns (regimes and counts), why to use it (discover availability), and any prerequisites (none). The enumerated regime list gives practical context for an agent deciding next steps.

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 description does not need to clarify parameters; it adds context by enumerating the regimes returned, which is output semantics rather than parameter semantics. No deduction is 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 lists every marketing-compliance regime NorthPoint can check, with specific examples (MiCA, FCA, GDPR, etc.) and includes rule counts. This distinguishes it from the sibling run_* tools that actually perform compliance checks.

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?

The description explicitly says 'Call this first to discover what is available,' which provides clear when-to-use guidance and implies this is a discovery tool before running specific checks. It does not explicitly name alternatives but the sibling tool names make the distinction obvious.

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