Check a URL against a WARDEN egress allowlist

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

Even with annotations declaring readOnlyHint, idempotentHint, and destructiveHint, the description adds substantial behavioral context: local URL parse, no DNS/HTTP, fail-closed empty allowlist, case-insensitive matching, wildcard semantics, and refusal of unparseable URLs. This fully discloses the tool's operational behavior.

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 well-organized into short labeled sections, front-loads the core purpose, and contains no filler. Each sentence adds meaningful guidance, from scope and exclusions to behavior and return shape.

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 read-only, idempotent two-parameter tool, the description is complete: it explains purpose, when to use it, when not to use it, behavior, return value, and an example. The existing output schema covers the detailed return structure, so no necessary information is missing.

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 schema already documents both parameters thoroughly. The description adds value beyond this with a concrete example call, wildcard behavior restated in practical terms, and the fail-closed empty allowlist note, which helps the agent form correct invocations.

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 states a specific verb and resource: 'Ask EgressGuard whether a URL's hostname is on an operator allowlist.' It clearly distinguishes itself from siblings by naming vet_mcp_server, static_scan_tools, and canonicalize_json as tools not to use for this purpose.

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 gives explicit 'When to use' and 'When NOT to use' sections, naming concrete alternatives and explaining the intended context: checking a host before a tool fetches or posts. It also specifies what the tool does NOT do, such as fetching the URL or inspecting tool text.

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