Sierra restructures the Agent Studio workflow around Ghostwriter
On November 2, 2026, Sierra announced a redesign of Agent Studio around its agent-building tool Ghostwriter, integrating troubleshooting, journey editing, and testing into a single conversation, with evidence, suggested changes, and test results kept together for teams to review before going live. Ghostwriter was launched on March 25, 2026, and initially could read SOPs, customer service call transcripts, photos of whiteboard sketches, process documents, recordings, and natural language instructions to identify key behaviors and edge cases; on September 28, 2026, it was expanded into a proactive collaborating member that resides in Slack and Teams. The new version supports maintaining context across journeys, simulations, and dashboards; each session is a chat thread containing conversation and changes, changes must be reviewed and merged, and sessions can be shared or forked; Agent Studio can also group related agents into the same project for unified testing and release, and offers line-by-line diffs, automated Agent Checks, peer review and a Reviewer role, staged releases, and rollback-capable immutable snapshots.
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The original article fully presents how Ghostwriter brings investigation, editing, testing, and approval into a single session, which can be used to understand how the agent-building process supports collaboration.
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Sierra announced on November 2, 2026 that it had redesigned Agent Studio around Ghostwriter, its agent-building agent, bringing investigation, journey editing and testing into one conversation. Evidence, proposed changes and test results remain together so teams can review them before anything goes live.
Previously, users had to move between different parts of Agent Studio to edit journeys, run simulations and review performance. The new workflow allows a user to ask why resolution rates dropped, examine conversations, update a journey and test the fix without leaving that conversation.
Sierra introduced Ghostwriter on March 25, 2026 as an agent for building other agents. Its original inputs included standard operating procedures, support-call transcripts, photographs of whiteboard sketches, process documentation, audio recordings and plain-English instructions. Ghostwriter uses those materials to identify key behaviors and edge cases for agents operating across voice, chat and email. On September 28, 2026, Sierra expanded it into an always-on, proactive teammate in Slack and Teams that can review customer interactions, suggest improvements and help turn them into experiments.
Persistent Context and Separate Sessions
Ghostwriter now remains available as users move among journeys, simulations and dashboards, and it can see the item currently being viewed. A user can ask about an apparent problem or have Ghostwriter address it without restating the surrounding context. The redesigned experience combines functions previously spread across Explorer, Sierra Assistant and other specialized agents, removing the need to know which tool handles a particular task.
Each session operates as a chat thread containing both the conversation and the changes Ghostwriter makes. Those changes stay in the session until someone reviews and merges them. Separate sessions allow a team to investigate an increase in customers requesting a support associate in one thread while building a new journey in another, without the two activities interfering with each other.
Sessions can be shared so colleagues can work through a problem together, or forked to continue where another user stopped. Before a merge, a user can also ask Ghostwriter to review a teammate’s changes.
Projects Spanning Multiple Agents
Agent Studio can now group related agents in a single project alongside the data and channels they share, allowing teams to test and release those agents together.
Sierra’s lender example assigns one agent to collect documents from applicants and another to manage the application and follow up until the loan closes. When the lender adds a document requirement, Ghostwriter updates both what the collection agent requests and how the application agent follows up within one session.
Testing, Approval and Rollout Controls
Line-by-line comparisons show exactly what Ghostwriter changed. Preview Chat and Simulations let teams test behavior before a merge, while release governance adds required approvals and controlled rollouts.
The supporting release-governance controls include Agent Checks, an automated linter that surfaces warnings based on journeys and the conversations they generate. Checks are prioritized by severity, and most include a suggested fix from Ghostwriter that can be applied in place. Organizations can also require Simulations to pass before a change moves toward production.
For human review, organizations can require peer review before release and use a Reviewer role to specify whose sign-off is needed, including a customer-experience lead, compliance stakeholder, engineering manager or another domain expert. Reviewers can inspect line-by-line diffs, leave contextual comments and request changes. Builders can work with Ghostwriter to address that feedback and request another review before a person approves the merge.
After approval, split-traffic releases can expose a change to part of customer traffic before expanding it more broadly. Each release is an immutable snapshot, supporting rollback if an unexpected problem appears.
The resulting workflow keeps investigation, editing, testing and review connected within a session, while merging and customer exposure remain subject to the team’s approvals and rollout controls.