fmsg-mcp

Send new fmsg message

send_message

Destructive

Send a new message immediately to start a new thread. Supports Markdown body, attachments, and multiple recipients; messages are immutable once sent.

Instructions

Send a new message immediately, starting a new thread. fmsg messages are immutable: once sent they cannot be edited or recalled. Send within the user's requested task or authorized automation. Recipients may be full @user@domain addresses or resolvable short names. The body is Markdown by default. Secrets (API keys, tokens) are redacted and the count reported. If the host rejects the message the host's own reason is returned verbatim. To continue an existing conversation use reply instead.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`to`	Yes	recipient addresses (@user@domain) or short names
`body`	Yes	message body; Markdown unless type says otherwise
`type`	No	body media type	text/markdown; charset=utf-8
`topic`	Yes	thread topic (subject) — immutable once sent
`no_reply`	No	ask recipients (and their agents) not to reply
`important`	No
`attachments`	No

Output Schema

TableJSON Schema

Name	Required	Description
`id`	Yes
`to`	Yes
`from`	Yes
`time`	Yes
`topic`	Yes
`warnings`	Yes
`parent_id`	Yes
`redactions`	Yes	secrets replaced with placeholders before sending
`attachments`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.3Sep 5, 2026

TDQS

A4.1/5.0

Behavior4/5

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

Annotations already establish write/destructive/idempotent traitshare. Description adds meaningful behavioral context: immutability (cannot edit/recall), secret redaction with count reporting, and verbatim return of host rejection reasons. This goes beyond annotation hints and helps an agent anticipate side effects.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Eight sentences, each carrying distinct information: purpose, immutability, authorization, recipients, body format, redaction, error behavior, and alternative. No filler, but slightly long; could be tightened without losing value.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With an output schema present I don't need to speculate on return values. The description covers the essential operational behavior: scope, side effects, security, and error handling. Minor omissions like attachment handling and rate limits are acceptable given the output schema and annotations.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema covers 71% of parameters. Description adds recipient address syntax detail and confirms Markdown default, but does not clarify the undocumented 'important' or 'attachments' parameters. Some added value, but gaps remain where description could compensate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

Description opens with 'Send a new message immediately, starting a new thread' – a specific verb, resource, and scope. It explicitly differentiates from reply ('To continue an existing conversation use reply instead'), making the tool's purpose unmistakable even without opening the schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Names reply as the alternative for continuing conversations, giving a clear when-to-use vs when-not-to-use. Also constrains usage to 'the user's requested task or authorized automation'. Does not mention other sibling tools, but reply is the primary competing action.

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

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