PRD Planning Pipeline
The planning pipeline transforms your project vision into a structured, executable plan. Understanding how it works helps you get better results.
How PRD Generation Works
When you click Generate PRD, Trinity runs a 4-phase pipeline. Each phase focuses deeply on one concern, producing better results than a single pass.
Phase 1: Architect
The architect phase designs the high-level structure:
- Phases — major development stages with clear objectives
- Epics — groups of related work within each phase
- Rationale — why things are organized this way
No stories are created yet — this phase focuses on getting the overall shape right.
Phase 2: Story Writer
The story writer creates individual stories within the epic structure:
- Story descriptions — clear, specific descriptions of what to build
- Acceptance criteria — measurable conditions for completion
- Story type — regular story, checkpoint, or quality checkpoint
Each story is scoped to be independently executable by an agent.
Phase 3: Dependency Mapper
The dependency mapper analyzes the stories and adds:
- Dependencies — which stories must complete before others can start
- Checkpoints — release gates placed at strategic points in the plan
- Story type refinements — marking checkpoint vs regular stories
This phase ensures stories execute in a valid order and that release gates are placed where they provide the most value.
Phase 4: Calibrator
The calibrator rates each story comparatively:
- Difficulty (1-5) — how complex the implementation is
- Surface area (small/medium/large) — how much of the codebase is touched
These ratings affect execution behavior — higher difficulty stories get more review passes, and the model tier may be upgraded for complex work.
Post-Pipeline Validation
After all four phases complete, Trinity runs validation:
- Vague AC detection — flags acceptance criteria that are too generic (e.g., "works correctly")
- Coverage check — verifies the plan covers all aspects of the roadmap
- Dependency validation — ensures no circular dependencies or missing references
Issues found are automatically fixed when possible.
Continuation Context
When generating PRD 2+, the pipeline receives context about previous work:
- Stories from earlier PRDs (completed, failed, skipped)
- Gotchas discovered during execution
- Execution summaries
This lets the new PRD build on existing work without duplicating effort or repeating mistakes.
Plan Review Best Practices
After generation, review your PRD before starting execution:
Check Story Scope
Each story should be:
- Specific — clearly defined, not vague
- Independent — executable on its own (given its dependencies)
- Testable — acceptance criteria that an agent can verify
Verify Dependencies
Look for:
- Stories that should depend on each other but don't
- Unnecessary dependencies that would serialize work that could run in parallel
- Missing checkpoint stories at important milestones
Adjust Difficulty Ratings
The calibrator does a good job, but you know your codebase best:
- A story touching unfamiliar third-party APIs might deserve a higher rating
- A story that's similar to existing code might deserve a lower rating
Check Checkpoint Placement
Checkpoints are release gates. Make sure they're at natural boundaries:
- End of a meaningful feature set
- Before a major architectural shift
- At milestones where you'd want to verify everything works together
Editing Stories
You can edit stories directly in the planning dashboard:
- Click a story to open its detail view
- Edit the description, acceptance criteria, or metadata
- Changes are saved immediately
You can also:
- Skip stories you don't want executed
- Adjust dependencies by editing the depends_on field
- Change difficulty/surface area ratings