# read_message_attachment

Read one exact attachment from one exact message in a permitted guild channel or thread as a native MCP image or audio block, with an embedded octet-stream fallback and an equivalent private resource link. The connector refetches current Discord evidence, validates the signed CDN route, refuses redirects and credentials, enforces the configured MCP response budget while streaming, verifies supported media signatures, persists nothing, omits delivery URLs and raw payloads from metadata, and wipes transient bytes after encoding.

Agent View of the PolicyLayer registry record for `read_message_attachment`. HTML page: https://policylayer.com/tools/app-lasers-guildcontrol-discord/read-message-attachment

## Facts

- Tool: `read_message_attachment`
- Server: GuildControl MCP (`guildctl`) — https://policylayer.com/tools/app-lasers-guildcontrol-discord.md
- Install: `npx -y guildctl`
- Homepage: https://github.com/j-256/guildcontrol
- Risk category: Read (Low risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Allowed

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "read_message_attachment",
    "arguments": {}
  }
}
```

## Why read_message_attachment is rated Low

Tool retrieves message attachments with no side effects, comprehensive safety controls, and no data modification or deletion.

From the tool's own definition: "Read one exact attachment from one exact message; refetches current Discord evidence; persists nothing."

## Use case

AI agents call read_message_attachment to retrieve information from GuildControl MCP without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

## Recommended policy (PolicyLayer)

Verdict: **Allowed**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches GuildControl MCP:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "read_message_attachment": {}
  }
}
```

## Other tools on GuildControl MCP (257)

- `delete_messages` — Destructive — https://policylayer.com/tools/app-lasers-guildcontrol-discord/delete-messages.md
- `execute_bulk_guild_ban` — Destructive — https://policylayer.com/tools/app-lasers-guildcontrol-discord/execute-bulk-guild-ban.md
- `execute_channel_deletion` — Destructive — https://policylayer.com/tools/app-lasers-guildcontrol-discord/execute-channel-deletion.md
- `execute_direct_message_change` — Destructive — https://policylayer.com/tools/app-lasers-guildcontrol-discord/execute-direct-message-change.md
- `execute_guild_application_command_change` — Destructive — https://policylayer.com/tools/app-lasers-guildcontrol-discord/execute-guild-application-command-change.md
- `execute_guild_departure` — Destructive — https://policylayer.com/tools/app-lasers-guildcontrol-discord/execute-guild-departure.md
- `execute_guild_integration_deletion` — Destructive — https://policylayer.com/tools/app-lasers-guildcontrol-discord/execute-guild-integration-deletion.md
- `execute_guild_prune` — Destructive — https://policylayer.com/tools/app-lasers-guildcontrol-discord/execute-guild-prune.md
- `execute_invite_deletion` — Destructive — https://policylayer.com/tools/app-lasers-guildcontrol-discord/execute-invite-deletion.md
- `execute_poll_end` — Destructive — https://policylayer.com/tools/app-lasers-guildcontrol-discord/execute-poll-end.md
- `execute_role_deletion` — Destructive — https://policylayer.com/tools/app-lasers-guildcontrol-discord/execute-role-deletion.md
- `execute_webhook_deletion` — Destructive — https://policylayer.com/tools/app-lasers-guildcontrol-discord/execute-webhook-deletion.md
- `execute_webhook_message_deletion` — Destructive — https://policylayer.com/tools/app-lasers-guildcontrol-discord/execute-webhook-message-deletion.md
- `plan_channel_deletion` — Destructive — https://policylayer.com/tools/app-lasers-guildcontrol-discord/plan-channel-deletion.md
- `plan_direct_message_change` — Destructive — https://policylayer.com/tools/app-lasers-guildcontrol-discord/plan-direct-message-change.md
- `plan_guild_departure` — Destructive — https://policylayer.com/tools/app-lasers-guildcontrol-discord/plan-guild-departure.md
- `plan_guild_integration_deletion` — Destructive — https://policylayer.com/tools/app-lasers-guildcontrol-discord/plan-guild-integration-deletion.md
- `plan_invite_deletion` — Destructive — https://policylayer.com/tools/app-lasers-guildcontrol-discord/plan-invite-deletion.md
- `plan_message_deletion` — Destructive — https://policylayer.com/tools/app-lasers-guildcontrol-discord/plan-message-deletion.md
- `plan_poll_end` — Destructive — https://policylayer.com/tools/app-lasers-guildcontrol-discord/plan-poll-end.md
- `plan_role_deletion` — Destructive — https://policylayer.com/tools/app-lasers-guildcontrol-discord/plan-role-deletion.md
- `plan_webhook_deletion` — Destructive — https://policylayer.com/tools/app-lasers-guildcontrol-discord/plan-webhook-deletion.md
- `plan_webhook_message_deletion` — Destructive — https://policylayer.com/tools/app-lasers-guildcontrol-discord/plan-webhook-message-deletion.md
- `compile_component_template` — Execute — https://policylayer.com/tools/app-lasers-guildcontrol-discord/compile-component-template.md
- `execute_announcement_crosspost` — Execute — https://policylayer.com/tools/app-lasers-guildcontrol-discord/execute-announcement-crosspost.md
- `execute_application_emoji_change` — Execute — https://policylayer.com/tools/app-lasers-guildcontrol-discord/execute-application-emoji-change.md
- `execute_application_entitlement_consumption` — Execute — https://policylayer.com/tools/app-lasers-guildcontrol-discord/execute-application-entitlement-consumption.md
- `execute_application_intent_enablement` — Execute — https://policylayer.com/tools/app-lasers-guildcontrol-discord/execute-application-intent-enablement.md
- `execute_application_test_entitlement_change` — Execute — https://policylayer.com/tools/app-lasers-guildcontrol-discord/execute-application-test-entitlement-change.md
- `execute_automod_change` — Execute — https://policylayer.com/tools/app-lasers-guildcontrol-discord/execute-automod-change.md
- …and 227 more: https://policylayer.com/tools/app-lasers-guildcontrol-discord.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=app-lasers-guildcontrol-discord · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/app-lasers-guildcontrol-discord