open_message_in_mailmate

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

With no annotations present, the description carries the full behavioral burden. It usefully discloses that the tool 'Activates MailMate' and navigates to the message, which signals a non-trivial side effect of bringing an external application to the foreground. It also clarifies the input format as a message:// URL, providing meaningful behavioral context beyond the tool name.

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 compact and front-loaded: the first sentence states exactly what the tool does, and the second sentence adds the key activation behavior. Every sentence earns its place, with no filler or redundant elaboration.

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 single-parameter tool with full schema coverage and an output schema, the description is largely complete. It covers the action, the input format, and the side effect of activating MailMate. A small gap is the absence of any guidance about when to prefer this tool over related siblings, but the simplicity of the tool keeps this from being a major omission.

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 already fully documents the single parameter with 'The message:// URL to open', and the description repeats the same concept without adding format details, validation rules, or edge-case guidance. Since schema description coverage is 100%, the baseline of 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 states a specific verb ('Open'), a specific resource ('a specific message in MailMate'), and the exact input type ('message:// URL'). It clearly distinguishes from sibling tools like get_message or get_message_link, since the goal is to open and navigate in the MailMate application rather than retrieve or link a message.

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 explicit guidance about when to use this tool versus alternatives such as get_message, get_message_link, or search_messages_tool. It implies usage by describing the action, but it does not state exclusions, prerequisites, or conditions that should route an agent to a sibling tool.

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