resolve-message-id

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

With no annotations, the description carries the full transparency burden. It explains how resolution works (via RFC822 Message-ID), what each input yields (numericId or null, plus messageId and resolvedCount), and includes a version note about flag coloring behavior. It stops short of explicitly stating non-destructiveness or edge-case behavior, but the disclosed behavior is substantive and above average.

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 well-structured with 'Use when', 'Returns', and 'Do not use when' sections, and it leads with the main use case. It is slightly verbose due to the version note, but every sentence adds information and the structure akes it easy to scan. A more compact phrasing might be possible, but the length is justified.

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 this is a simple one-parameter tool with an output schema, the description fully covers when to use it, how it behaves, what it returns, and how it differs from alternative tools. The version note adds important contextual information. No critical gaps remain.

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 coverage is 0%, so the description must explain the parameter. It clarifies the `ids` format (either numeric or `imap:` prefixed) and what happens to each form (numeric pass through, `imap:` resolved). This goes well beyond the raw JSON schema pattern and provides essential semantic context.

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 that this tool resolves `imap:` message IDs into numeric Mail.app IDs, specifically needed for reply-to-message/forward-message. It distinguishes itself from sibling tools by noting that flag/move/mark tools work directly with `imap:` IDs, making this tool's unique purpose explicit.

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 explicit 'Use when' and 'Do not use when' guidance, including concrete examples (reply-to-message/forward-message) and exclusions (numeric IDs already pass through, flag/move/mark operate directly). It also notes a version-specific change (2.10.0) that affects when this tool is needed for flag colors, showing strong awareness of alternatives.

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