Parallel Planner Protocol

Analyze task steps — which ones must wait for each other, which ones can run simultaneously? Build a dependency graph, form parallel groups, and prevent conflicts.

Core principle: Sequential is safe but slow. Parallel is fast but requires care. Making the right distinction is this skill's job.

Parallelization Criteria

A step can run in parallel only if all conditions are met:

• Not dependent on another step's output
• Does not write to a resource another step reads (no write conflict)
• Does not modify shared state (global variable, same file)
• If it fails, it does not block other parallel steps

A step must run sequentially if any of these apply:

• Its input is another step's output
• It writes to the same file / DB table / API resource
• Order matters for correctness (e.g., schema before data)
• Must be atomic (inside a transaction)

Parallelizable Work Types

Conflict Detection

After identifying parallel candidates, check for conflicts:

Write-Write Conflict

Two steps write to the same resource → cannot be parallel. Solution: Run sequentially OR write to separate files, then merge.

Read-Write Conflict

One step reads while another writes to the same resource → cannot be parallel. Solution: Read first, then write (sequential).

Resource Contention

Shared rate limits or connection pools → limit parallel count. Solution: Cap at 3 parallel, run in batches.

Ecosystem Index

When the steps come from an ecosystem workflow, steps that share a parallel group in that workflow are already known to be independent; start from those groups instead of re-deriving them.

Pick the ecosystem whose domain matches the request and follow its workflow map. If the ecosystem skill is not installed, use the workflow ids above as the plan skeleton and run each member skill directly, or install it with npx skills add fatih-developer/fth-skills --skill <ecosystem> after the user agrees. Never invent skills that are not listed.

Output Format

PARALLEL PLANNER
Total steps: N | Parallel groups: N | Sequential steps: N
Estimated speedup: ~X% faster

## Dependency Graph
[mermaid or text visualization]

## Execution Plan

### Group 1 — Parallel (N steps)
- [ ] #A: [step]
- [ ] #B: [step]
- [ ] #C: [step]
-> All complete, then proceed to Group 2

### Group 2 — Sequential
- [ ] #D: [step]  (requires: #A, #B)
- [ ] #E: [step]  (requires: #D)

## Conflict Warnings
[If any — blocked parallel candidates and reason]

## Steps Kept Sequential
| Step | Reason | Depends On |
|------|--------|------------|
| #D | Uses #A output | #A |

Speed Estimate

Sequential total = Sum(all step durations)
Parallel total   = Sum(longest step per group)
Speedup          = (Sequential - Parallel) / Sequential * 100

Complexity-based estimates when duration is unknown:

• Simple (file read, short code): ~1 unit
• Medium (API call, analysis): ~3 units
• Heavy (web research, large code): ~5 units

When to Skip

• 2 or fewer steps — parallelization is meaningless
• All steps are sequentially dependent
• User said "do it step by step"
• Transaction-bound operations (must be atomic)

Guardrails

• Never parallelize write operations to the same resource — even if it seems safe.
• Always show the dependency graph — the user must see why steps are ordered this way.
• Cross-skill: works with task-decomposer (provides the step list) and tool-selector (optimizes tool usage within groups).

References

• references/EXAMPLES.md — dependency graphs and parallel execution plans for real tasks. Read it when the expected output format or level of detail is unclear.

🔗 Next Steps & Handoffs

Ecosystem: @ecosystem-orchestration — Agent Orchestration.

Workflows:

• Complex Task Execution Flow (orch-complex-task, step 2 of 6): next → @tool-selector (optional).

Handoff contract: pass results to the next skill through an inline Handoff block in your reply with the fields skill, workflow, created_at, inputs, summary, and next (the handoff contract of @ecosystem-orchestration). If a next skill is not installed, continue with its step from the ecosystem map, or install it with npx skills add fatih-developer/fth-skills --skill <name> after the user agrees.