# Runtime Flow Analysis

> Trace a runtime operation end-to-end, record candidate claims, verify important behavior, and promote only claims that pass source verification, counterexample search, and scope checks.

- Skill: `tuana-vn/runtime-flow-analysis` (Agent Skill)
- Install (CLI): `npx skillmds@latest add tuana-vn/runtime-flow-analysis`
- Raw SKILL.md: https://api.skillmd.com/api/skills/tuana-vn/runtime-flow-analysis/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: tuana-vn (https://skillmd.com/u/tuana-vn)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/tuana-vn/runtime-flow-analysis

---


# Runtime Flow Analysis — 4.0

## Start

Read canonical memory:

- `00_current_understanding.md`
- `00_evidence_ledger.md`
- `00_master_decision_matrix.md`

Read `00_hypotheses.md` and `00_open_questions.md` only if relevant.

## Trace

Generic control-flow target:

```text
Inbound trigger
→ entry handler
→ validation/conversion
→ service/use-case
→ orchestration
→ abstraction
→ selector/factory/provider
→ concrete implementation
→ real boundary
→ result/error mapping
```

Trace data flow in parallel whenever a value influences an external result:

```text
input / trigger
→ source retrieval
→ source field/data
→ parse/decode
→ transform/normalize
→ mapping/state
→ serialization/output
→ observable result
```

Control flow and data provenance are separate evidence dimensions. Prove both when needed.

## Scope Isolation

When multiple endpoints/operations/modes reach shared code, record the exact scope of each branch.

Do not transfer a condition observed in one entry point to another entry point merely because they share a downstream method.

## Field / Data Provenance

For externally meaningful fields/data, record:

| Surface | Field/Data | Trigger/Condition | Retrieval | Source | Transform | Mapping/State | Output | Evidence |
|---|---|---|---|---|---|---|---|---|

A conditional external result may be implemented by conditional retrieval earlier in the flow.
Do not infer that the output layer itself must contain the condition.

## Record Candidates First

New non-trivial findings start as CANDIDATE.

Do not write directly to canonical baseline.

## For Each Candidate

1. define exact scope
2. locate supporting source
3. verify runtime wiring when relevant
4. identify concrete implementation
5. search for counterexamples
6. inspect alternate branches/configuration where relevant
7. assign Evidence ID
8. for output/data claims, prove provenance through to observable result
9. search for alternate entry points or earlier conditional retrieval that could contradict the claim
10. decide:
   - PROMOTE
   - KEEP AS HYPOTHESIS
   - REJECT
   - LEAVE UNKNOWN

## Runtime Model and Diagram Requirement

For each materially distinct externally significant flow family, update `docs/reverse-engineering/models/runtime_flow_catalog.md` with:

| Flow | Entry | Validation | Orchestration | State/Integration | Result/Error Mapping | Observable Effect | Evidence |
|---|---|---|---|---|---|---|---|

For the primary representative full-system flow, create/update:

```text
docs/reverse-engineering/diagrams/03_primary_runtime_sequence.md
```

It must contain a Mermaid `sequenceDiagram` and an `Evidence Anchors` section. A class list or prose-only flow is insufficient.

## Output

Detailed flow:
`docs/reverse-engineering/flows/<operation>.md`

Canonical updates:
only PROMOTED VERIFIED facts.

Hypotheses:
write non-promoted findings to `00_hypotheses.md`.

## Completion Gate

A runtime-flow document is incomplete when an applicable item is unresolved without explanation:

```text
[ ] entry-point scope is explicit
[ ] callers and downstream effects are traced far enough to classify exposure
[ ] branch conditions are not generalized beyond proven scope
[ ] externally meaningful field/data provenance is traced when applicable
[ ] observable result/error mapping is proven
[ ] alternate paths/counterexamples were searched
[ ] unresolved links remain hypotheses/unknowns rather than promoted facts
[ ] material flow is represented in the runtime flow catalog
[ ] primary full-system flow has an evidence-linked Mermaid sequence diagram
```