thunderbird_send_email

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

No annotations are provided, so the description carries the full behavioral burden. It does disclose two useful traits: the message is plain-text only, and delivery goes through the account's own outgoing mail server rather than a shared relay. It does not state authentication requirements, whether sending is confirmed to the user, or what happens on SMTP failure — and the truncation cuts off any further disclosure.

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 with the verb leading, no filler, and the differentiating detail (own outgoing mail server) placed early. The only structural defect is that the text terminates mid-word, which is an artifact rather than padding, but it does leave the sentence incomplete.

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 send/mutation tool with zero annotations and no output schema, the description should cover prerequisites (connected account), recipient/body expectations, and error behavior. Instead it is truncated and silent on all of these, leaving the agent without enough context to invoke it reliably despite the sibling namespace being crowded with competing send tools.

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 schema declares zero parameters with no description gaps, and the rule assigns a baseline of 4 in that case. The description adds one meaningful constraint not expressible in an empty schema — that the body must be plain text — but it cannot supply recipient/subject/body semantics because no parameters are declared.

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+resource (sends a plain-text message) and scopes it to a Thunderbird account using that account's own outgoing mail server, which distinguishes it from the many other send_email siblings (m365_send_email, outlook_send_email, proton_send_email, send_email). However, the text is truncated mid-sentence, so the full scope of what it does cannot be confirmed.

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?

No when-to-use or when-not-to-use guidance is given beyond the implied 'use this for Thunderbird accounts.' With siblings like send_email, proton_send_email and outlook_send_email in the same namespace, the description should explicitly route the agent (e.g., 'use when the sender account is a Thunderbird account'). Nothing indicates prerequisites such as thunderbird_connect being required first.

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