list_registries

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

Description claims read-only behavior ('List'), but annotations set destructiveHint=true, creating a direct contradiction. This misleads the agent about tool effects.

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?

Three concise sentences front-loaded with an emoji. Every sentence provides essential information without redundancy.

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, read-only tool, the description fully covers purpose, usage order, and relation to siblings. No gaps given the simplicity.

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?

No parameters exist, so description cannot add parameter details. Baseline of 4 is appropriate as schema coverage is 100% and description avoids redundancy.

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?

Description clearly identifies the tool as 'List all available MCP registries' with a specific verb and resource. It distinguishes itself by instructing to use it first before 'search_servers', a sibling tool.

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?

Explicitly states 'Use this FIRST' and references the alternative tool 'search_servers'. Provides context on why registries are important for finding servers to add as upstreams.

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