List data sources

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds transparency about the return structure: each data source has specific fields, exactly one type object, and fileInput for file feeds. This is valuable context beyond the annotations, helping the agent know what to expect in the response even though there is no output schema. It does not contradict annotations.

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 three sentences and information-dense. The first sentence defines the action, the second lists the output fields, and the third explains a primary use case. Every sentence adds value, though the second sentence is a bit long. It is structured and front-loaded with the main purpose.

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 tool is a simple listing operation with no output schema and strong parameter documentation, the description covers the essential context: it explains the return data structure and gives a concrete usage scenario. It does not explicitly mention pagination behavior, but the schema's page_token description already covers that. The description is sufficient for an agent to select and invoke the tool correctly.

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%, with each parameter (account, page_size, page_token) fully described inline. The description does not add any additional meaning about parameters beyond what the schema already provides. It focuses on the return data and usage, which is useful but not parameter-specific. Baseline 3 is appropriate.

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 explicitly states the tool 'Lists the data sources of an account' – a specific verb and resource. It also describes the key fields of each data source (name, dataSourceId, displayName, input, type object, fileInput), which clearly distinguishes it from sibling tools like get_data_source and list_promotions. The purpose is unambiguous and complete.

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 a clear use case: 'Use it to find the API-type data source that insert_product_input / insert_promotion require as data_source.' This directly tells when to use the tool. However, it does not explicitly mention when not to use it or provide an alternative reference (e.g., get_data_source for a single data source), so it falls short of a 5.

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