Skip to main content
Glama
combor

Baryon MCP

save_draft

Destructive

Create or replace a Proton Mail draft with optional HTML, plain-text body, and file attachments, including threading headers.

Instructions

Create a complete Proton Mail draft, or replace an existing draft when uid and uidvalidity are provided. Supports plain text, an optional HTML alternative, and bounded attachments supplied either inline as base64 (content_base64) or as an absolute path to a local file that the server reads at save time (content_path). To reply inside a thread, read the message with get_email and set in_reply_to to its message_id, and references to its references followed by its message_id; when it reports no references, use its in_reply_to in their place so earlier ancestry survives. A replacement keeps the previous draft's Message-ID, plus whichever of its In-Reply-To and References the call omits; passing an empty array for either removes it, detaching the draft from its thread. Updating appends the replacement before removing the old UID; inspect warning if cleanup was incomplete.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
ccNoCc recipient addresses
toNoTo recipient addresses
bccNoBcc recipient addresses retained in the saved draft
uidNoexisting draft UID to replace; requires uidvalidity
fromYessender address; must be one of the Proton account addresses exposed by Bridge
subjectNo
html_bodyNooptional HTML alternative, up to 50000 characters
text_bodyNoplain-text body, up to 50000 characters
referencesNoconversation chain: the parent email's references followed by its message_id; set together with in_reply_to so clients thread the reply; when replacing a draft, omit to keep the existing header or pass an empty array to remove it
attachmentsNoregular file attachments; at most 100 and 25 MB decoded in total
in_reply_toNoMessage-IDs this draft replies to, normally just the message_id of the email being answered; angle brackets optional; when replacing a draft, omit to keep the existing header or pass an empty array to remove it
uidvalidityNoDrafts UIDVALIDITY accompanying uid

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault
uidYesUID of the newly saved draft
folderYes
warningNo
uidvalidityYesDrafts folder generation accompanying uid
replaced_uidNo
previous_draft_removedYes
Behavior5/5

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

Beyond the destructiveHint annotation, the description discloses substantial behavioral details: replacement keeps the old Message-ID, omitting In-Reply-To/References preserves them while empty arrays remove them, updating appends before removing the old UID, and warns to inspect if cleanup was incomplete. It also explains attachment ingestion modes (base64 vs path) and their constraints.

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?

The description is dense but every sentence earns its place. It front-loads the primary purpose, then efficiently covers replacement semantics, threading rules, attachment modes, and cleanup warnings without repetition or filler.

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?

Given the tool's complexity (12 parameters, replacement semantics, attachment constraints, threading behavior), the description covers all essential aspects: creation vs replacement, threading workflow, attachment limits and formats, and operational caveats. An output schema exists, so omitting return-value details is acceptable.

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

Parameters5/5

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

Although schema coverage is high (92%), the description adds significant meaning to parameters: it explains how in_reply_to and references must be set together for threading, how omission vs empty arrays behaves during replacement, and how content_base64/content_path are mutually exclusive alternatives. This goes well beyond the schema's field-level descriptions.

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?

The description opens with a specific verb and resource: 'Create a complete Proton Mail draft, or replace an existing draft when uid and uidvalidity are provided.' This clearly states the tool's core purpose and distinguishes it from sibling tools like save_attachment, get_email, or list_emails.

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?

The description gives clear usage context, including when to replace drafts (when uid and uidvalidity are provided) and a concrete workflow for replying inside a thread ('read the message with get_email and set in_reply_to to its message_id...'). It does not explicitly state when not to use the tool, but the context is strong enough to guide selection.

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

Install Server

Other Tools

Latest Blog Posts

MCP directory API

We provide all the information about MCP servers via our MCP API.

curl -X GET 'https://glama.ai/api/mcp/v1/servers/combor/baryon-mcp'

If you have feedback or need assistance with the MCP directory API, please join our Discord server