Convert MBOX archive

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

With no annotations, the description carries the full burden and does so well: it discloses size and message-count bounds, truncation signalling (truncated=true), rejection cases, the non-destructive guarantee ('The source archive is never modified'), collision-safe report output, and the absence of cancellation. These are exactly the operational traits an agent needs before committing to a long-running conversion.

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?

Front-loaded with the core action, then organized into labelled blocks ('Bounded:', output behavior, 'Returns a JSON summary'). Dense but every sentence adds distinct operational information; nothing is filler.

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 16-parameter tool with no annotations, it covers purpose, bounds, failure handling, side effects, and return shape (with the output schema handling the rest). An agent has enough to call it correctly and knows the edge cases that cause rejection or truncation.

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% across 16 parameters, yet the description only explains two of them (output_directory is required, bundles=true switches to bundle directories). The remaining toggles (preset, thread_mode, strip_*, embed_inline_images) are undocumented, though most have self-describing names. Partial compensation only.

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 and resource ('Convert one flat .mbox archive ... to Markdown files') and immediately narrows scope with 'flat' plus rejection of compressed archives and Apple Mail .mbox directories. This lets an agent distinguish it from convert_eml and convert_directory without opening another schema.

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?

It gives concrete when-to-use conditions (archive must be ≤256 MiB, ≤1000 messages) and an explicit alternative path ('use the dead-letter CLI for larger archives'). It does not directly route between convert_mbox, convert_eml, and convert_directory, but the format constraints make the boundary largely inferable.

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