Mailbox MCP

Mark emails as unread

mark_unread

Idempotent

Mark messages as unread, restoring the state they were in before something marked them read. This is the undo for mark_read, and it is the one to reach for when a triage pass marked more than the person meant. Pass the whole set in ONE call. Verified the same way mark_read is: the flags are read back off the server, so a message that could not be changed is named rather than assumed done. A uid only means something in the folder it came from, so pass mailbox when the uids did not come from INBOX. Marking a message that is already unread changes nothing and is not an error. It does not touch anything else - a message stays flagged, answered and where it was.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`uids`	Yes	The UIDs to act on, from list_emails or search_emails. Pass EVERY message you want changed in ONE call - this tool acts on the whole set in a single operation, and doing it that way costs the user one call instead of one per message. Up to 500 at a time. A single message is simply a one-element array.
`mailbox`	No	IMAP folder name. Defaults to INBOX.

Schema Changelog

Changes observed during successful MCP inspections. Dates show when Glama detected each change.

First observedSep 5, 2026

TDQS

A4.5/5.0

Behavior4/5

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

Annotations indicate readOnlyHint=false, idempotentHint=true, openWorldHint=true; description goes well beyond them: it explains verification behavior by reading flags back off the server, names failure behavior (a message that could not be changed is named), says already-unread messages change nothing without error, and confirms non-interference with other message states. It does not annotate response structure, but no output schema exists and the added behavioral detail is substantial.

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?

The description is efficient and front-loaded: the core purpose appears in the first sentence, and operational guidance follows in short, focused sentences. It is slightly long, but nearly every sentence earns its place by addressing a concrete decision or expectation. No fluff, no repetition of schema basics.

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?

For a mutating tool with no output schema, the description covers the essential operational contract: intended result, batching, mailbox scoping, idempotency, failure verification, and non-interference. It does not state the return type or exact response fields, but the tool's verification semantics are explained. Given sibling context, the description is one of the strongest in the set.

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 100%, and both parameters have schema descriptions. The description still adds meaning: it explains why to pass the whole set in one call, the 500 limit implication, mailbox's role when uids did not come from INBOX, and that a one-element array is valid for a single message. This is meaningful semantic enrichment beyond the schema.

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 states a specific verb and resource: 'Mark messages as unread', then immediately clarifies the intended state restoration semantics. It explicitly distinguishes itself from mark_read by framing this as the undo operation. The title also aligns, making the purpose unmistakable.

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

Usage Guidelines5/5

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

The description explicitly says this is the undo for mark_read and 'the one to reach for when a triage pass marked more than the person meant'. It also tells the agent to pass the whole set in ONE call and to pass mailbox when uids did not come from INBOX, with clear guidance for already-unread messages. This is direct usage guidance and scenario-based routing.

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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TDQS

A4.3/5.0

Disambiguation4/5

Most tools target clearly distinct actions and resource types, and the near-overlapping pairs (archive_email vs move_email, check_bounces vs check_receipts) are explicitly cross-referenced in their descriptions. However, the delivery-status pair genuinely overlaps — both scan inbound mail to answer "did my message get there?" — and archive_email is functionally a role-aware move_email, so an agent could still select the wrong one without careful reading.

Naming Consistency4/5

Virtually every tool follows a consistent verb_noun pattern with clear prefix families (check_*, create_*, draft_*, list_*, mark_*, read_*). The single outlier is not_junk, which breaks the mark_* symmetry of its counterpart mark_junk and is not a standard verb-noun construction, though it remains perfectly readable.

Tool Count3/5

31 tools is firmly in the heavy range, though email is a genuinely broad domain spanning send/reply/forward, three draft variants, folder management, flags, junk handling, and diagnostics. Real consolidation was possible — check_bounces and check_receipts could be one delivery-status tool, archive_email is a special case of move_email, and the read-state/flag pairs could take boolean parameters — but each tool has a defensible job.

Completeness4/5

The core email lifecycle is thoroughly covered: send/reply/forward, three draft types plus draft editing, read/search/list/thread, full folder CRUD, move/archive/delete, flags, read state, junk handling, and file-upload intake. Minor gaps exist — there is no permanent-deletion or purge tool, no filter/rules management, and identity/contact maintenance is deliberately out of scope — but real user workflows can be completed without dead ends.

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