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Glama

nylas

by io.usefulapi

Send an email

nylas_send_message
Destructive

SENDS a real email via the connected account. This dispatches an actual message. Nylas v3: POST /v3/grants/{grant_id}/messages/send.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
ccNoCC email addresses (array of strings).
toYesRecipient email addresses (array of strings).
bccNoBCC email addresses (array of strings).
bodyNoEmail body (HTML or plain text).
subjectNoEmail subject line.
grant_idNoConnected-account grant id. Overrides NYLAS_GRANT_ID for this call.
reply_to_message_idNoId of the message this is a reply to.

Schema Changelog

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

  1. First observed

TDQS

A3.5/5.0
Behavior3/5

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

The description confirms the destructive nature of sending an email, matching the destructiveHint annotation. However, it does not disclose additional behaviors such as rate limits, authorization details beyond grant_id, or what happens on failure.

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 concise with one functional sentence and the API endpoint reference. Every part is relevant, but the API path could be considered technical noise.

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

Completeness2/5

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

For a tool with 7 parameters and no output schema, the description lacks information about return values, side effects (e.g., saved sent message), or behavior of reply_to_message_id, making it incomplete for full understanding.

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?

With 100% schema description coverage, the baseline is 3. The tool description adds no extra meaning beyond the schema's parameter 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 clearly states 'SENDS a real email via the connected account' using a specific verb and resource, and distinguishes from sibling tools like nylas_create_draft by emphasizing actual dispatch.

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

Usage Guidelines3/5

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

The description implies use for sending emails but lacks explicit guidance on when to use this tool versus creating a draft or alternatives. No exclusions or prerequisites are mentioned.

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

A3.7/5.0
Disambiguation5/5

Each tool targets a distinct resource and action: create vs list vs get for specific entities like draft, event, calendar, contact, grant, message, folder. There is no overlap, as even similar verbs like 'list' are paired with unique nouns. Agents can easily select the correct tool.

Naming Consistency5/5

All tool names follow a uniform 'nylas_verb_noun' pattern using snake_case, with clear and predictable verbs (create, get, list, send) and nouns (draft, event, calendar, etc.). The naming is fully consistent across all 15 tools.

Tool Count5/5

With 15 tools, the set is well-scoped for a Nylas integration covering email, calendar, and contacts. Each tool serves a clear purpose without redundancy, and the count falls comfortably within the ideal range of 3-15 tools.

Completeness3/5

The tool set covers reading and limited creation (drafts, events) but lacks update and delete operations for all entities, as well as create for contacts. This leaves notable gaps for full lifecycle management, though core workflows like listing and fetching are present.

Resources