find_by_msgid

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

With no annotations, the description carries the full burden. It discloses that the tool looks up across all projects and that results can include multiple projects. It does not cover error behavior, rate limits, or authentication, but for a simple lookup tool the core behavior is adequately described.

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 two sentences long, front-loads the purpose, and contains no filler. Every sentence adds value: the first states the action, the second explains its cross-project nature and use case.

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 simple tool with one parameter and no output schema, the description is mostly complete. It explains the cross-project behavior and offers usage guidance. It does not describe the return format, but given its role as a discovery tool, the current description is sufficient.

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 input schema covers the only parameter (msgid) with a description about angle brackets. The tool description does not add new parameter details beyond restating the schema. Since schema coverage is 100%, a baseline score 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 clearly states the tool's purpose: 'Look up patches and cover letters by Message-Id across all projects.' It specifies the resource (patches and cover letters), the key (Message-Id), and the scope (across all projects), which distinguishes it from siblings like get_patch and get_series that likely operate within a single project.

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 guidance: 'Use this to discover the projects + series ids before drilling in.' It explains that a single Message-Id can appear under multiple projects, which informs usage. However, it does not explicitly state when not to use this tool or list alternatives, though the sibling names imply other tools for different purposes.

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