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<img src="assets/synapse.svg" alt="Synapse Logo" width="150"/>
</p>
# Synapse
[](https://hex.pm/packages/synapse)
[](https://hexdocs.pm/synapse)
[](https://hex.pm/packages/synapse)
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Version: v0.1.0 (2025-11-11)
Synapse is a headless, declarative multi‑agent runtime for code review orchestration. It exposes a signal bus API (`Synapse.SignalRouter`) and a workflow engine with Postgres persistence so you can submit review work, fan it out to specialists, negotiate conflicts, and consume structured summaries — all without a Phoenix UI.
Highlights
- Declarative orchestrator runtime (no GenServer boilerplate)
- Signal bus with typed topics and contract enforcement
- Specialist agents defined via actions + `state_schema`
- Workflow engine with persistence and audit trail (`workflow_executions`)
- LLM gateway powered by `Req` with OpenAI and Gemini providers
- Telemetry throughout (router, workflows, LLM requests)
## Quick Start
1. **Install dependencies**
```bash
mix setup
```
2. **Create and migrate the database**
By default, dev connects to `postgres://postgres:postgres@localhost:5432/synapse_dev`. Override via `POSTGRES_*` env vars (see config/dev.exs).
```bash
mix ecto.create
mix ecto.migrate
```
3. **Run the Stage 2 demo (optional sanity check)**
```bash
mix run examples/stage2_demo.exs
```
This boots the runtime, publishes a review request, and prints the resulting summary so you can see the declarative orchestrator in action.
4. **Start the runtime for development**
```bash
iex -S mix
```
This boots `Synapse.Runtime`, the signal router, the orchestrator runtime (reading `priv/orchestrator_agents.exs`), and the workflow engine with Postgres persistence. The application is OTP‑only — no Phoenix endpoint is required.
## Submit a Review Request
Publish a `:review_request` signal from CI, a script, or an iex session:
```elixir
{:ok, _signal} =
Synapse.SignalRouter.publish(
Synapse.SignalRouter,
:review_request,
%{
review_id: "PR-12345",
diff: git_diff,
files_changed: 12,
labels: ["security"],
intent: "feature",
metadata: %{repo: "org/app", author: "alice", files: touched_paths}
},
source: "/ci/github"
)
```
The coordinator workflow classifies the request, spawns security/performance specialists as needed, and persists every step to `workflow_executions`.
## Consume Results
Subscribe to summaries if you want push-style notifications:
```elixir
{:ok, _sub_id} = Synapse.SignalRouter.subscribe(Synapse.SignalRouter, :review_summary)
receive do
{:signal, %{type: "review.summary", data: summary}} ->
IO.inspect(summary, label: "Review complete")
end
```
Or query Postgres for historical/auditable data:
```elixir
Synapse.Workflow.Execution
|> where(review_id: "PR-12345")
|> Synapse.Repo.one!()
```
Each execution record includes the workflow name, step-by-step audit trail, accumulated results, and the final status, so you can drive dashboards or rerun failed work.
## Orchestrator & Specialists
Specialists and the coordinator are declared in `priv/orchestrator_agents.exs` and are reconciled and run by `Synapse.Orchestrator.Runtime`. Update this file to add or tune agents — no GenServer code needed.
Example snippet:
```elixir
%{
id: :coordinator,
type: :orchestrator,
actions: [Synapse.Actions.Review.ClassifyChange],
orchestration: %{
classify_fn: &MyStrategies.classify/1,
spawn_specialists: [:security_specialist, :performance_specialist],
aggregation_fn: &MyStrategies.aggregate/2,
negotiate_fn: &MyStrategies.resolve_conflicts/2
},
signals: %{subscribes: [:review_request, :review_result], emits: [:review_summary]},
state_schema: [review_count: [type: :non_neg_integer, default: 0]]
}
```
On boot, the orchestrator runtime validates configs, spawns any missing agents, and monitors process health. Update the file and trigger a reload to reconcile changes.
## Declarative Workflow Engine
The workflow engine executes declarative specs (steps + dependencies) with retries, compensation, and telemetry. It powers specialist runs and the coordinator paths while giving you a uniform audit trail and optional Postgres persistence.
Key pieces
- Spec: `Synapse.Workflow.Spec` with `Step` and `Output` helpers
- Engine: `Synapse.Workflow.Engine.execute/2` runs the spec and emits telemetry
- Persistence (optional): snapshots to `workflow_executions` via `Synapse.Workflow.Persistence`
Minimal example
```elixir
alias Synapse.Workflow.{Spec, Engine}
alias Synapse.Workflow.Spec.Step
spec =
Spec.new(
name: :example_workflow,
description: "Analyze and generate critique with retries",
metadata: %{version: 1},
steps: [
Step.new(
id: :fetch_context,
action: MyApp.Actions.FetchContext,
# env = %{input, results, context, step, workflow}
params: fn env -> %{id: env.input.review_id} end
),
Step.new(
id: :analyze,
action: Synapse.Actions.CriticReview,
requires: [:fetch_context],
retry: [max_attempts: 3, backoff: 200],
on_error: :continue,
params: fn env -> %{diff: env.input.diff, metadata: env.results.fetch_context} end
),
Step.new(
id: :generate_critique,
action: Synapse.Actions.GenerateCritique,
requires: [:analyze],
params: fn env ->
review = env.results.analyze
%{
prompt: "Summarize issues",
messages: [%{role: "user", content: Enum.join(review.issues || [], ", ")}],
profile: :openai
}
end
)
],
outputs: [
Spec.output(:review, from: :analyze),
Spec.output(:critique, from: :generate_critique, path: [:content])
]
)
input = %{review_id: "PR-42", diff: "..."}
ctx = %{request_id: "req_abc123"} # required when persistence is enabled
case Engine.execute(spec, input: input, context: ctx) do
{:ok, %{results: _results, outputs: outputs, audit_trail: audit}} ->
IO.inspect(outputs.critique, label: "Critique")
IO.inspect(audit.steps, label: "Audit trail")
{:error, %{failed_step: step, error: error, audit_trail: audit}} ->
IO.inspect({step, error}, label: "Workflow failed")
IO.inspect(audit.steps, label: "Audit trail")
end
```
Parameters and env
- Step params may be a map/keyword, or a function `fn env -> ... end` where `env` includes `:input`, `:results`, `:context`, `:step`, and `:workflow`.
- Steps support `requires: [:other_step]`, `retry: [max_attempts:, backoff:]`, and `on_error: :halt | :continue`.
- Outputs map step results to the final payload; `path` lets you pick nested fields; `transform` is available for custom shaping.
Persistence
- Dev config enables persistence by default: see `config/config.exs` for `config :synapse, Synapse.Workflow.Engine, persistence: {Synapse.Workflow.Persistence.Postgres, []}`.
- When persistence is enabled, you must provide a `:request_id` in `context`; the engine will snapshot before/after steps to `workflow_executions`.
- You can override per call: `Engine.execute(spec, input: ..., context: ..., persistence: nil)`.
Telemetry
- Emits `[:synapse, :workflow, :step, :start|:stop|:exception]` with metadata like `:workflow`, `:workflow_step`, `:workflow_attempt`.
- Example handler:
```elixir
:telemetry.attach(
"wf-logger",
[[:synapse, :workflow, :step, :stop]],
fn _evt, m, meta, _ ->
require Logger
Logger.info("step done",
workflow: meta.workflow,
step: meta.workflow_step,
attempt: meta.workflow_attempt,
duration_us: m.duration_us
)
end,
nil
)
```
Error and result shapes
- Success: `{:ok, %{results: map(), outputs: map(), audit_trail: map()}}`
- Failure: `{:error, %{failed_step: atom(), error: term(), attempts: pos_integer(), results: map(), audit_trail: map()}}`
Further reading
- Cookbook: `docs_new/workflows/engine.md`
- ADR: `docs_new/adr/0004-declarative-workflow-engine.md`
## LLM Providers (Req)
Synapse uses `Req` for HTTP and provides a multi‑provider LLM gateway. Configure at runtime via environment:
```bash
export OPENAI_API_KEY=sk-...
# or
export GEMINI_API_KEY=ya29....
```
Configuration is assembled in `config/runtime.exs`. Profiles support timeouts, retries, and provider‑specific options.
Example usage:
```elixir
{:ok, resp} =
Synapse.ReqLLM.chat_completion(%{
messages: [%{role: "user", content: "Summarize the following diff..."}],
temperature: 0.2
}, profile: :openai)
resp.content # normalized string content
resp.metadata # token usage, finish_reason, provider-specific details
```
See: `lib/synapse/req_llm.ex`, `lib/synapse/providers/*`, and `docs_new/20251029/implementation/LLM_INTEGRATION.md`.
## Persistence
- Adapter: `Synapse.Workflow.Persistence.Postgres`
- Schema: `workflow_executions` (created by migration at `priv/repo/migrations/*_create_workflow_executions.exs`)
- Test env disables persistence by default (`config/test.exs`)
Common tasks:
```bash
mix ecto.create
mix ecto.migrate
mix ecto.rollback
```
Database configuration for dev can be overridden with `POSTGRES_HOST`, `POSTGRES_DB`, `POSTGRES_USER`, `POSTGRES_PASSWORD`, `POSTGRES_PORT`, `POSTGRES_POOL_SIZE`.
## Telemetry
- Signals: `[:synapse, :signal_router, :publish|:deliver]`
- LLM: `[:synapse, :llm, :request, :start|:stop|:exception]`
- Workflows/Orchestrator: see `docs_new/20251028/remediation/telemetry_documentation.md`
Attach your own handlers using `:telemetry.attach/4`.
## Tests
Run the full suite with:
```bash
mix test
```
Dialyzer and other pre-commit checks are available via `mix precommit`.
## Roadmap & Docs
- Roadmap: `ROADMAP.md`
- Orchestrator design and reference: `docs_new/20251028/synapse_orchestrator/README.md`
- Multi‑agent framework docs: `docs_new/20251028/multi_agent_framework/README.md`
- Workflow engine and persistence: `docs_new/workflows/engine.md` and ADRs in `docs_new/adr/`
- Post‑Phoenix direction: `docs_new/20251109/README.md`
## Changelog
See `CHANGELOG.md`.
## Tags
elixir • otp • jido • req • multi‑agent • orchestrator • workflows • llm • openai • gemini • postgres • telemetry
## License
Licensed under MIT. See [LICENSE](LICENSE).
