list_sources

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

With no annotations, the description fully discloses behavior: it explains automatic paging due to CTM's per_page cap, the truncation warning when max_items is exceeded, and the default filtering to active sub-accounts. These details go well beyond the schema and are essential for correct invocation.

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 succinct yet information-dense: three sentences cover purpose, paging behavior, and status parameter. Every sentence earns its place, and the most critical information is front-loaded.

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 listing tool with no annotations, the description provides robust operational details: paging, truncation, default filtering, and parameter guidance. The output schema handles return-value documentation. The only notable gap is the lack of account_ids semantics, which prevents a perfect score.

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?

Although schema description coverage is 0%, the description adds meaning for max_items (raising it for large lists), status (accepted values), and per_page (context about CTM's cap). However, account_ids is omitted entirely, leaving its purpose and format unspecified. The description partially compensates for the schema gap but does not cover all parameters.

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 opens with 'List tracking sources (channels, campaigns) across sub-accounts,' which specifies a clear verb, resource, and scope. It distinguishes itself from siblings like get_source (which retrieves a single source) and list_sub_accounts (which lists accounts).

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 provides clear operational context: it explains the default behavior (active sub-accounts), how to change the status filter, and when to increase max_items for large source lists. It does not explicitly name alternative tools, but the scope is clear enough that an agent would know when to invoke this versus a get_* or report tool.

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