Session types

Planning session

A planning session forms a hypothesis. The agent reviews the problem description and code context, then produces a proposed plan: a list of steps with expected test outcomes. No code changes during a planning session.

• Input: problem description, attached code context
• Output: proposed plan with steps and expected test outcomes
• Proof: none — proof comes later
• Gate: operator approval required before the next session can run

Implementing session

An implementing session executes the approved plan. The agent applies changes, runs tests, and records results. The session output is a diff plus test results.

• Input: approved plan, prior session context
• Output: code diff, test results
• Proof: diff is evidence, not yet verified proof
• Gate: diff review by operator before moving to VERIFYING

Verifying session

A verifying session collects evidence and produces a verification report. The agent re-runs the test suite, reviews the diff, and checks case memory for prior failures. Output becomes a proof candidate.

• Input: diff, test suite, case memory
• Output: verification report — pass/fail with specific evidence items
• Proof: verified report is the proof required to move to RESOLVED
• Gate: at least 1 verified proof item required for RESOLVED transition

How session limits count

Each session of any type counts as one session toward your plan’s monthly limit. Running a planning session, an implementing session, and a verifying session on the same Work item = 3 sessions.

How to start each type

Start sessions from the Sessions tab in the Zero console, or via the API:

POST /cases/:id/sessions{"type": "planning" | "implementing" | "verifying"}

The type field is required. Zero validates that the requested type is valid for the Work item’s current state — e.g. an implementing session cannot start if no plan has been approved.