create_emails_ereader_devices

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

Annotations already declare idempotentHint=true, destructiveHint=false, and readOnlyHint=false, so the safety profile is covered. The description adds the instruction to read the GET/schema first, which is a useful behavioral hint about how to discover the request format. However, it does not disclose other behavioral traits such as what happens if the device does not exist (e.g., does it create or error), whether this operation affects existing devices, or what the response contains. The 'Update' behavior is mentioned but conflicts with the tool name's 'create' prefix, which is a transparency issue.

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 concise, using two sentences and a structured 'Args:' block. It front-loads the core action ('Update e-reader devices.') and includes the full endpoint URL, making it easy to scan. The structure is efficient, though the brevity sacrifices necessary details, which is factored into other dimensions.

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?

The tool has one complex object parameter, an output schema exists, and there are many related siblings. The description only instructs to read the GET/schema for fields, which is helpful but insufficient for context. It does not explain what an e-reader device is in this context, how it relates to email, or how it differs from 'create_me_ereader_devices'. The name-description mismatch adds ambiguity. An agent would need additional inference or external knowledge to use this 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?

The schema has only a 'body' parameter with additionalProperties: true, essentially a free-form object with no described fields (0% coverage). The description says 'body: Request payload. Read the matching GET or the /schema endpoint first to see the fields this resource expects.' This provides meaningful guidance on how to determine the actual fields, compensating for the lack of schema detail. While it does not list any specific fields, it directs the agent to a discovery mechanism, which is useful but not complete.

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 'Update e-reader devices.' and provides the endpoint POST /api/emails/ereader-devices, which clearly specifies an action and resource. However, the tool name is 'create_emails_ereader_devices' while the description says 'Update', creating a mismatch that could confuse an agent. Additionally, it does not differentiate this tool from closely named siblings like 'create_me_ereader_devices' or 'create_emails_send_ebook_to_device', so the purpose is not fully unambiguous.

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 no guidance on when to use this tool versus alternatives. It only instructs the agent to read the matching GET or /schema endpoint before sending the body, which is a usage hint for constructing the request but not for choosing this tool over others. There is no mention of exclusions or comparisons to sibling tools.

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