Convert email

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

With no annotations, the description carries the full burden and does well: it discloses that full Markdown is returned, that output_path additionally writes to disk, that attachments are listed but not decoded to disk, and the nuanced forwarding/quoted-text behavior in thread_mode. It omits error behavior and the exact effect of the unmentioned flags, which keeps it from a 5.

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-loads the core purpose, then delivers return behavior, the attachment caveat, thread-mode nuance, and a scannable preset list. Every sentence carries information and nothing is padded.

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?

An output schema exists, so the description needn't restate return values, and it appropriately focuses on behavior an agent can't infer. For a 14-parameter tool with zero schema documentation, the few flags left unexplained (thread_order, embed_inline_images, no_calendar_summary) are the only real gap.

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 description coverage is 0% across 14 parameters, so the description must compensate, and it does for the critical ones: it enumerates the four preset values, defines the preset-to-flag mapping, states that individual flags override the preset, and explains output_path and thread_mode. It leaves several booleans (embed_inline_images, no_calendar_summary, thread_order) unexplained, so compensation is strong but incomplete.

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?

States a specific verb and resource ('Convert a .eml email file to Markdown with YAML front matter') and immediately clarifies the output shape. It also names the sibling convert_eml_to_bundle for the attachment-saving case, so an agent can separate this tool from its neighbors without opening a 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?

Gives clear routing advice for the attachment case ('use convert_eml_to_bundle to save the decoded attachment files') and explains when each preset applies and when thread_mode="structured" is appropriate. It stops short of contrasting with convert_mbox or convert_directory, which the sibling list shows are plausible alternatives.

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