carrel_mail

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

With no annotations, the description carries the full burden. It does convey that the attachments action writes files into a directory and that the threads action consumes either a file or a directory, which is useful behavior context. But it does not disclose overwrite/suffixing semantics (left to the force param), permissions, or whether the threads action writes anything or merely returns data.

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?

A single front-loaded sentence naming the file type first, then the two modes. Efficient with no filler, though the two-mode construction is slightly dense and could be split for scanability.

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 five-parameter tool with no annotations or output schema, the description covers the core mode split and the differing path semantics. The remaining gap is what the threads action returns versus writes, which an agent might need to interpret results correctly.

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 80%, so the schema itself documents path, root, force, and out_dir well. The description only restates the path semantics already present in the schema and adds nothing about root, force, or out_dir. Baseline 3 is appropriate when the schema does the heavy lifting.

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 resource (eml/mbox email files) and two concrete operations (extract attachments, group messages into threads). It is clearly distinguishable from generic siblings like carrel_pack or carrel_convert, though it never names a sibling to differentiate against.

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 two listed behaviors implicitly map to the two enum actions, giving an agent a rough idea of when each mode applies. However, there is no explicit 'use this when...' guidance, no exclusions, and no pointer to any sibling tool for adjacent email tasks.

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