proton-bridge-mcp

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Reply

reply

Destructive

Compose and send a threaded email response to one message while preserving alias masking and threading; choose all recipients or save as a draft for review.

Instructions

Reply to one message with correct threading. Replies to the Reply-To address when there is one, so alias mail stays masked. Pass all=true to reply to everyone, with your own addresses removed from Cc and duplicates dropped. Pass draft=true to save it for review, or confirmed=true to send.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "uid": "<uid>",
      "body": "<body>"
    },
    "name": "reply"
  }
}

Input Schema

Name	Required	Description
`all`	No	Reply to everyone on the message, not just the sender. Default false.
`uid`	Yes
`body`	Yes	Your reply text. The original is quoted beneath unless quote=false.
`draft`	No	Save to Drafts instead of sending. Needs no confirmation because nothing goes out.
`quote`	No	Quote the original beneath your reply. Default true.
`attach`	No	Files to attach, by path. Only from the allowed source directories.
`folder`	No	Folder holding the message. Default INBOX.
`dry_run`	No	Preview exactly what would happen and change nothing. Needs no confirmation.
`subject`	No	Override the auto 'Re: ...' subject.
`confirmed`	No	Required to actually send. Not needed when draft=true.
`uidvalidity`	No	UIDVALIDITY for that folder; refuses on mismatch.
`from_address`	No	Must be on the sender allowlist. Left unset, alias mail automatically uses the alias-owner address.

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv2.0.0Oct 24, 2026

addedInput schema / properties / all

Added value: +{
+  "description": "Reply to everyone on the message, not just the sender. Default false.",
+  "type": "boolean"
+}

First observedv1.2.1Aug 11, 2026

TDQS

A4.2/5.0

Behavior4/5

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

Annotations declare destructive=true, openWorld=true and non-idempotent, so the safety bar is partly met; the description adds real value by disclosing the send-gating flow (draft vs confirmed), the dry_run preview, and alias-masking behavior on the From/Reply-To side. It stops short of saying what a failed send or UIDVALIDITY mismatch does to state, and there's no output description.

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

Conciseness5/5

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

Three sentences, all load-bearing: purpose first, then reply-all semantics, then the send/draft gate. No filler and no restatement of the title.

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

Completeness5/5

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

For a 12-parameter mutation tool with no output schema but full annotations and 92% schema coverage, the description covers the decisions an agent must get right: how to preview, how to park a draft, how to actually send, and how reply-all and alias addresses behave. Remaining details live in the schema where they belong.

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

Parameters4/5

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

Schema coverage is already 92%, so the baseline is 3; the description still earns credit by explaining effects the schema doesn't state — that all=true strips your own addresses from Cc and dedupes, and that replies route to Reply-To to keep aliases masked. It omits attach/quote/folder/subject details, but those are covered in-schema.

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

Purpose4/5

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

Opens with a specific verb+resource ('Reply to one message') and immediately names the defining trait ('correct threading'), which separates it from send/forward. It doesn't explicitly name those siblings, so the agent must infer that forwarding or new mail goes elsewhere.

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?

Gives concrete routing conditions: all=true for reply-all, draft=true to park for review, confirmed=true to actually send. It implies that draft=true is the alternative to sending, but never names send/forward/create_draft/send_draft as siblings, so cross-tool selection is only partially covered.

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