Curated tool names (v2 server): createReaction, updateReaction, deleteReaction, getReactions, getReactionsStats, markReactionsRead, getPinnedReactions, togglePinnedReaction. Call them by these exact names.

Simulator.Company Reactions Specialist

Reactions are the comments / events / approvals / ratings that live under an actor. They are themselves actors, organised as a hierarchical (threaded) tree, so a reaction can reply to another reaction.

Relationship to the other skills

• simulator-actors — the actor's own data fields (a reaction is about an actor, not its data).
• simulator-attachments — files attached to a reaction or actor (a reaction can carry attachments).
• simulator-graph — graph structure (links/layers), unrelated to reactions.

The one rule that trips everyone up: actorId vs reactionId

Every reaction path is addressed by the parent (root) actor, while the reaction's own id travels separately:

• actorId (path) = the parent actor whose reaction tree you are working in.
• reactionId (body, on update/delete/pin) = the specific reaction to act on.
• parentId (on create) = the reaction you are replying to (omit for a top-level comment).

The tools expose these as distinct arguments, so you never collide the two.

Workspace context

Reactions are addressed by actorId (a UUID), so no accId is needed. Make sure you have the target actor's UUID (use simulator-actors / searchActors to find it) before commenting.

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Comment on an actor

createReaction(
  type="comment",                 # everyday note; other types: view, rating, sign, ds, done, reject, freeze; ai = agent reply (see below)
  actorId="<parent actor UUID>",
  description="Looks good to me",  # the comment text
  notify=true)                     # default true; set false to post quietly

Reply in a thread — pass the parent reaction's id as parentId:

createReaction(type="comment", actorId="<parent actor UUID>",
  description="Agreed", parentId="<reaction UUID being replied to>")

Attach files by passing attachments (ids from uploadBase64 / getAttachments, see simulator-attachments):

createReaction(type="comment", actorId="<actor UUID>", description="see attached",
  attachments=[{ "attachId": 5521 }])

Edit / delete a reaction

updateReaction(actorId="<parent actor UUID>", reactionId="<reaction UUID>",
  description="Updated note")
deleteReaction(actorId="<parent actor UUID>", reactionId="<reaction UUID>")   # irreversible — confirm first

Read reactions

getReactions(actorId="<parent actor UUID>", view="tree", limit=30)   # view: tree | flat | thread
getReactionsStats(actorId="<parent actor UUID>")                     # counts by type, etc.

• view=tree returns the nested reply tree; flat a flat list; thread a single thread.
• parentId narrows to the replies under one reaction; from/to filter by created time.

AI agent reactions (extra.mcp)

A reaction can be handed to the platform's AI agent by creating it with extra.mcp = true. The platform then runs the agent on that reaction under the requesting user's access (the agent uses this same MCP server, so it can only read/write what the user can) and posts the answer back as a child ai reaction.

createReaction(type="comment", actorId="<actor UUID>",
  description="Summarize this actor and flag anything unusual",
  extra={ "mcp": true })            # → triggers the AI agent; its reply appears as a child `ai` reaction

The ai reply carries a reasoning object that the agent streams while it works:

• reasoning.inProgress — true while the agent is still producing the answer.
• reasoning.thoughts — [{ id, text, createdAt }], a step log (e.g. tools it used).
• description — fills with the answer text (streamed live over WebSocket, then finalized).

So when reading a discussion (getReactions), an ai reaction with reasoning.inProgress = true is still being written; treat its description as partial.

Don't loop: the agent already replies on its own. Only set extra.mcp on a human request you want the agent to handle — not on the agent's own output. The platform bounds runaway chains, but creating extra.mcp reactions from agent output wastes turns.

When the agent runs, the client also passes a UI-context object (control-events-context) that says where the user is — activeActor, activeReaction, activeLayer, activeGraph, page, hostOrigin, workspaceId, graphDiscovery. Read it to resolve "here" / "this actor" / "this layer" and to default ids the user left implicit. See $CLAUDE_PLUGIN_ROOT/docs/entities/ui-context.md.

Attachments: actor vs. message are two different sets. Attachments are a per-actor linked collection, and a reaction is itself an actor — so there are two places a file can live, each read with getActorAttachments(<id>) → readAttachment:

• The actor's own files ("files on this actor / the attachments tab") → getActorAttachments(activeActor).
• A file the user attached to their message ("do you see the file I sent?") → the triggering message is a reaction under activeActor, so its file lives on that reaction, not on the actor. Use the reaction's id: prefer activeReaction from the UI context; if absent, find the trigger via getReactions(actorId=activeActor, view="flat", orderValue="DESC") — the newest human reaction (the one with extra.mcp) — and pass its id to getActorAttachments.

Pick the set the user means; if it's ambiguous, check both (the actor and the triggering reaction).

Embed a smart form, an actor card, or chips

A reaction can carry more than text:

• Run a Smart Form (script) in the reaction — set appId to a Smart Form (CDU/Script app) actor id (+ optional appSettings {autorun, expired, users, groups, fullWidth}): createReaction(type="comment", actorId="<actor>", appId="<smartFormActorId>", appSettings={autorun:true}). (The same appId/appSettings embed a smart form into a regular actor — see simulator-smart-forms.)
• Nested actor card — extra.linkedActorId embeds another actor as a preview card: createReaction(..., extra={ "linkedActorId": "<otherActorId>" }).
• Inline chips / rich text — description renders BBCode: chips [actor=<id>]Label[/actor], [application=<smartFormId>]Label[/application], [user=…], [event=…]; formatting [b], [color=…], [h2], [ul][*]…[/ul], [url=…]; and [md]…[/md] for markdown. Fetch the environment's exact tag set with getBbcodeTags. BBCode works only OUTSIDE [md] blocks — keep chips/BBCode out of any [md]…[/md] section. And the reverse: description is BBCode by default, not markdown, so any markdown you write MUST be wrapped in [md]…[/md] (e.g. [md]## Title\n- item[/md]) or it renders as literal text. See docs/entities/reactions.md.

Pin & read state

getPinnedReactions(actorId="<parent actor UUID>")
togglePinnedReaction(actorId="<parent actor UUID>", reactionId="<reaction UUID>", pinned=true)
markReactionsRead(actorId="<parent actor UUID>", count=12)   # clears the unread badge

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Reference Documents

Path	When to read
$CLAUDE_PLUGIN_ROOT/docs/entities/reactions.md	Reaction model, types, tree structure, data shape
$CLAUDE_PLUGIN_ROOT/docs/entities/attachments.md	Attaching files to a reaction

Tips

• actorId is always the parent actor; the reaction's own id is reactionId (update/delete/pin).
• type="comment" is the default note; the full set is view/comment/ai/rating/sign/ds/done/reject/freeze — reserve sign/ds/done/reject for real approval / sign-off / completion flows (there is no approve type).
• Reply by setting parentId; omit it for a top-level comment.
• notify=false posts without sending notifications (it is honoured — sent explicitly).
• deleteReaction is irreversible — confirm with the user first.
• To attach a file, upload it first (uploadBase64 → attachId) then pass attachments:[{attachId}] — see simulator-attachments.