himalaya-mcp

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flag_email

Add or remove email flags such as Seen, Flagged, Answered, or Draft to track message status. Specify a message ID, flags, and whether to add or remove them.

Instructions

Add or remove flags on an email. Flags: Seen, Flagged, Answered, Draft (and Deleted on himalaya v1 only; on v2 delete by moving to the trash with move_email). Use 'add' to set flags, 'remove' to clear them.

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": {
      "id": "<id>",
      "flags": "<flags>",
      "action": "<action>"
    },
    "name": "flag_email"
  }
}

Input Schema

Name	Required	Description
`id`	Yes	Email message ID
`flags`	Yes	Flags to add/remove (e.g. ['Seen', 'Flagged'])
`action`	Yes	Whether to add or remove the flags
`folder`	No	Folder name (default: INBOX)
`account`	No	Account name (uses default if omitted)

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedv2.2.2Nov 7, 2026

addedInput schema / properties / id / anyOf

Added value: +[
+  {
+    "type": "string"
+  },
+  {
+    "maximum": 9007199254740991,
+    "minimum": 0,
+    "type": "integer"
+  }
+]

removedInput schema / properties / id / type
```
Removed value: -"string"
```

First observedv1.7.0Jun 21, 2026

TDQS

A4.2/5.0

Behavior4/5

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

With no annotations, the description carries the full burden and does well: it makes clear this is a mutation with two directions, and discloses a version-dependent behavioral quirk (Deleted flag only exists on himalaya v1; on v2 deletion is a move to trash). It omits permissions, account requirements, and what happens for an unknown id or invalid flag string.

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 tight sentences, front-loaded with the purpose, then the value vocabulary, then the action semantics. The version caveat is placed inline as a parenthetical rather than bloating the text, and nothing is redundant.

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 5-parameter mutation tool with no annotations and no output schema, the description gives an agent enough to call it correctly: what it changes, the legal flag values, and the migration caveat. The remaining gap is error/response behavior, which matters more here because no output schema exists to describe it.

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 coverage is 100%, so the baseline is 3; the description then adds real value by listing the valid flag names (Seen, Flagged, Answered, Draft) that the free-form string array in the schema does not constrain, and by explaining the action enum's effect. Still, it does not clarify whether arbitrary/custom flags are accepted or how folder and account interact with id lookup.

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?

States a specific verb pair plus resource ('Add or remove flags on an email') and immediately enumerates the flag vocabulary. It also differentiates itself from the sibling move_email by naming it as the correct tool for deletion, so an agent can route without opening either 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?

Explains the add vs remove action semantics ('Use add to set flags, remove to clear them') and gives one explicit routing rule — deletion on himalaya v2 should go through move_email instead. It stops short of broader when-not guidance (e.g. when to prefer this over compose/draft_reply for the Draft flag), but the key exclusion is covered.

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