> ## Documentation Index
> Fetch the complete documentation index at: https://c42d5cb-opencomputer.manicule.dev/llms.txt
> Use this file to discover all available pages before exploring further.
> For every page in one file, fetch https://c42d5cb-opencomputer.manicule.dev/llms-full.txt (large).
> To search and read these docs as tools, connect the MCP server at https://c42d5cb-opencomputer.manicule.dev/api/mcp.
> Every agent surface: https://c42d5cb-opencomputer.manicule.dev/.well-known/llms-manifest.json
# Linked and spawned threads (/slack/linked-and-spawned-threads)
Related: [Threads](/slack/threads.md), [Shared threads](/slack/shared-threads.md), [Mid-turn messages](/slack/mid-turn-messages.md), [Permission modes](/slack/permission-modes.md), [Approvals, questions and plans](/slack/approvals-questions-plans.md), [Subagents](/slack/subagents.md)
> A pasted Slack permalink is read only if everyone involved can see it; `spawn_thread` starts a parallel session from a pushed brief
## Pasted links
When a message to the session contains a Slack message permalink, the gateway attaches the linked thread: its first message, the linked reply and the latest replies. The model receives it marked as data from Slack, not as instructions.
* At most 3 links per message are read; size limits are in Limits and defaults.
* The link must be in the same Slack workspace, and `@computer` must be a member of the conversation it points to.
* If reading takes more than 10 seconds, the message is delivered with a note that reading took too long.
* Messages forwarded into the message (up to 3) are attached with no access check.
### Access check
A linked thread is attached only if all of these can see the linked conversation:
1. The person who posted the link.
2. The session's owner.
3. Everyone in the session's conversation, when it is not the linked one.
| Linked conversation | Who counts as able to see it |
| --------------------- | --------------------------------------------------------------------------------- |
| Public channel | Every full member of the Slack workspace; a guest only if a member of the channel |
| Private channel or DM | Its members. Refused when the session's conversation is a public channel. |
The check also refuses when the session's conversation is shared with another organization, or when a member list it has to read has more than 5,000 members. On a refusal the model gets a note with the reason in place of the content.
## Reading and posting tools
Gateway-and-host deployment only. Parameters: Agent tools.
| Tool | What it does | Limits |
| ------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------ |
| `read_thread` | Reads a thread by link, or by channel id and message timestamp. Same content and access check as a pasted link, with the session's owner as the asker. | 40 calls per runner. Never asks for approval. |
| `post_thread` | Posts a reply into another thread for the owner. | 20 calls per runner. 4,000 characters. Asks for approval unless the mode is `bypassPermissions`. |
`post_thread`:
* replies in the thread, never at the channel's top level;
* neutralizes `@channel`, `@here`, `@everyone` and user-group mentions;
* appends a line: "Posted for @owner from this thread." with a link back.
## Spawned threads
`spawn_thread` starts a new session, in a new thread, that runs in parallel. Gateway-and-host deployment only. Parameters: Agent tools.
| Stage | Who | What happens |
| ----- | ----------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Brief | Agent | Writes a Markdown file in a workspace repository, commits it and pushes it to that repository's default branch. The tool refuses a brief that is not there. |
| Call | Agent | Calls `spawn_thread` with a one-line `task`, the `brief` path and optionally a `model` tier. Outside `bypassPermissions` the call asks for approval. |
| Post | Gateway | Posts a top-level message in the parent's channel: a mention of the owner, the task, a link to the brief and a link back to the parent thread. |
| Start | New session | Runs on that message as if the owner had mentioned `@computer` there. It is told to read the brief first and report there. |
| The new session's | Value |
| ---------------------- | ------------------------------------------------------- |
| Owner, permission mode | The parent's |
| Model | The parent's, unless a `model` argument overrides it |
| Conversation | Its own |
| Session directory | Its own, starting from each repository's default branch |
| Context | The pushed brief only |
* 8 spawns per runner.
* The parent is not told when the child finishes. The child reports in the brief and in its own thread; the parent can read that thread with `read_thread`.
* Steer or stop the child in its own thread. Stopping the parent does not stop it.