list_directories

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

Annotations already declare readOnlyHint=true; the description adds that the tool returns directoryId in the format 'POOL_...' and that it is needed for other tools. This goes beyond annotations by hinting at the output structure, though it does not detail pagination 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 consists of two short, front-loaded sentences that deliver purpose and usage guidance with no extraneous 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?

Given the low complexity (2 optional parameters, fully described schema, read-only annotation), the description is nearly complete. It explains the purpose, output value, and usage context. Minor omission: no mention of pagination in the description, but the schema covers it.

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 description coverage is 100%, so the schema already documents both parameters (pageSize and skipToken). The description adds no additional meaning beyond what the schema provides, hence a baseline of 3.

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 'List the XM Directories (contact pools) available to this account', specifying the verb (list) and resource (directories/contact pools). It also distinguishes this tool from siblings by highlighting that it is used to discover the directoryId required by other mailing-list and contact tools.

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 instructs to 'Use this first to discover the directoryId... that every mailing-list and contact tool requires.' This provides a clear when-to-use directive, indicating this tool is a prerequisite for other operations.

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