[&] Protocol Documentation¶
Welcome to the documentation hub for the [&] Protocol.
The [&] Protocol is a language-agnostic specification for capability composition in AI agents. It defines how an agent declares what it can remember, how it reasons, how it understands time and space, how it is embodied (perception/action/affordance), how those capabilities compose, and how that declaration can compile into downstream runtime artifacts such as MCP and A2A configurations.
Use this documentation to understand the protocol from multiple angles:
Architecture explains the system model, runtime lifecycle, and end-to-end declaration flow.
Positioning compares [&] with adjacent standards and research.
Competitive Landscape maps the machine cognition market and explains the structural constraints facing each competitor category.
Topology Is the Authority explains why governance must emerge from feedback topology, not be bolted onto architecture.
Autonomous Systems explains why autonomous vehicles and drone swarms are the canonical [&] use case, including the Palantir integration surface and κ-driven swarm governance.
Research provides the motivation for a composition layer in the agent stack.
FAQ answers common questions quickly.
Ecosystem Overview explains how all twelve products compose through the six primitives.
Industry Verticals maps seven commercial industries where all six primitives deliver value.
Capability pages explain the six core primitives in more detail.
Skills are hands-on, step-by-step guides covering the full declare → validate → compose → generate workflow, plus provider implementation, governance, and integration patterns.
What you’ll find here¶
A practical overview of the protocol’s role in the agent stack
A runtime walkthrough covering declaration → validation → composition → resolution → generation
Explanations of capability declaration, contracts, provenance, and governance
Comparisons with MCP, A2A, ACP, and related work
Deep dives into
&memory,&reason,&time,&space,&body, and&governSkills guides for hands-on implementation — from writing your first
ampersand.jsonto building providers and governance policies
Documentation map¶
Homepages
Root Docs
[&] Protocol Docs
- Five-Minute Quickstart (Elixir Reference CLI)
- Architecture Guide
- 1. What the protocol is responsible for
- 2. Stack position
- 3. Core architectural model
- 4. Repository architecture
- 4.1 Overview
- 4.2 Why this structure matters
- 5. Schema architecture
- 5.1
ampersand.schema.json - 5.2
capability-contract.schema.json - 5.3
registry.schema.json - 5.4 Why multiple schemas are better
- 6. Declaration architecture
- 6.1 Top-level shape
- 6.2 Capability binding modes
- 6.3 Why declarations are object-shaped
- 7. Composition architecture
- 7.1 Set-like semantics
- 7.2 Conflict behavior
- 7.3 Why composition is separate from execution
- 8. Pipeline architecture
- 8.1 The role of
|> - 8.2 Contract-driven validation
- 8.3 Architectural implication
- 9. Governance architecture
- 9.1 Components
- 9.2 Why governance is modeled this way
- 9.3 Architectural boundaries
- 10. Provenance architecture
- 10.1 What provenance captures
- 10.2 Why hash-linked chains matter
- 10.3 Architectural role
- 11. Provider architecture
- 11.1 Capabilities are interfaces
- 11.2 Providers are implementations
- 11.3 Why this separation matters
- 12. Registry architecture
- 12.1 What the registry publishes
- 12.2 Why a registry exists
- 12.3 Architectural boundary
- 13. Generation architecture
- 13.1 MCP generation
- 13.2 A2A generation
- 13.3 Architectural significance
- 14. Reference implementation architecture
- 14.1 Why the reference implementation is minimal
- 14.2 Why a CLI matters
- 15. Documentation architecture
- 16. End-to-end architecture flow
- 16.1 Minimal runtime walkthrough
- 16.2 What happens during
validate - 16.3 What happens during
compose - 16.4 What happens during execution
- 16.5 What happens during
generate - 16.6 Failure behavior
- 17. Example mental model
- 18. Non-goals of this architecture
- 19. Design principles for future architecture work
- 20. Practical reading order
- 21. Summary
- Runtime Walkthrough
- 1. What this walkthrough is
- 2. A minimal declaration
- 3. Step 1: schema validation
- 4. Step 2: normalization and composition
- 5. Step 3: contract checking
- 6. Step 4: provider resolution
- 7. Step 5: generation into downstream artifacts
- 7.1 MCP generation
- 7.2 A2A generation
- 8. Step 6: runtime execution and provenance emission
- 9. What failure looks like
- 10. What governance does during runtime processing
- 11. Reference lifecycle summary
- 12. What is normative and what is illustrative
- 13. Why this walkthrough matters
- 14. Short summary
- [&] Ecosystem Overview — How Everything Ties Together
- The Missing Layer: Capability Composition in the Agent Protocol Stack
- Competitive Landscape: Machine Cognition
- Topology Is the Authority: Why Agent Governance Can’t Be Bolted On
- The $48B problem nobody is solving correctly
- The insight: feedback loops determine who gets to decide
- Why this matters for enterprise deployment
- The autonomy-coherence gradient
- The portfolio as topology
- The competitive landscape, reframed
- Why existing machine cognition systems can’t get here
- What investors should be watching
- The thesis in one sentence
- Autonomous Systems: The Canonical [&] Use Case
- Why autonomous vehicles and drones
- 1. Where [&] sits in the autonomy stack
- 2. Why all six primitives are load-bearing
- 3. Governance as constraint envelope
- 4. The disconnected operations problem
- 5. Swarm governance through κ
- 6. Manned-unmanned teaming (MUM-T)
- 7. The Palantir integration
- 8. What [&] explicitly does not do
- 9. Platform applicability
- 10. The provenance requirement
- Summary
- Industry Verticals: Where All Six Primitives Compose
- [&] vs MCP vs A2A vs DALIA vs ACP
- Research Overview
- Executive Summary
- 1. Why This Research Matters
- 2. The Current Protocol Stack
- 3. Research Thread: Cognitive Architectures
- 4. Research Thread: Memory Systems
- 5. Research Thread: Reasoning and Deliberation
- 6. Research Thread: Time and Temporal Intelligence
- 7. Research Thread: Space and Spatial Intelligence
- 8. Research Thread: Taxonomy and Functional Decomposition
- 9. Research Thread: Provenance, Auditability, and Trust
- 10. Research Thread: Governance as Data
- 11. Why a Composition Layer Is Plausible Now
- 12. What the [&] Protocol Adds
- 13. Important Open Questions
- 14. Reading Map
- 15. Conclusion
- Suggested Next Reading
- FAQ
- What is the [&] Protocol?
- What problem does it solve?
- Does [&] replace MCP?
- Does [&] replace A2A?
- Why is the protocol called “[&]”?
- What are the six core capability domains?
- What is
ampersand.json? - Why use JSON instead of a language-specific DSL first?
- What does a capability declaration look like?
- What is a provider?
- Can multiple providers satisfy the same capability?
- What is
provider: "auto"? - Why is
needrequired whenproviderisauto? - What is capability composition?
- Why do algebraic properties matter here?
- What is the difference between
&and|>in the protocol? - What are capability contracts?
- What do
accepts_fromandfeeds_intomean? - What is type-safe pipeline validation in this context?
- What is provenance in the [&] Protocol?
- Why is provenance a protocol concern instead of just an implementation detail?
- What is governance in the protocol?
- What is the difference between hard and soft governance constraints?
- What does
escalate_whendo? - Is the protocol only for autonomous agents?
- Is the protocol only for LLM agents?
- Does the protocol depend on Elixir?
- Why keep a reference implementation at all if the protocol is language-agnostic?
- What is the current reference implementation capable of?
- What does the CLI do today?
- What is generated by
generate mcp? - What is generated by
generate a2a? - What does “compile into MCP + A2A” mean?
- Is the schema the source of truth?
- Why have multiple schemas instead of only
ampersand.schema.json? - What is the capability registry?
- Do you need a registry to use the protocol?
- Can the protocol be useful before a full ecosystem exists?
- Is the protocol intended for public standards work or private internal use?
- How is this different from “agent frameworks with memory modules”?
- Is the protocol trying to standardize all of agent architecture?
- How should contributors think about future work?
- What should not be added casually?
- Who is this repository for right now?
- Where should a new reader start?
- What is the shortest possible summary?
Capabilities & Registry
- Capability Registry Pages
&memory: Capability Deep Dive&memory.episodic— Experience, Session History, and Replayable Context&memory.graph— Graph-Structured Memory Capability&reason: Deliberation, Evaluation, and Decision-Making&reason.argument— Evidence-Weighted Deliberation for the [&] Protocol&reason.deliberate— κ-Aware Deliberation for the [&] Protocol&reason.attend— Proactive Attention and Bounded Autonomy for the [&] Protocol&time: Temporal Intelligence in the [&] Protocol&time.forecast— Forecasting as a Capability&space: Spatial Intelligence for Agents&space.fleet— Fleet State, Regional Context, and Spatial Operations&govern: Cross-Cutting Governance for Agents&govern.telemetry— Observability, Cost Tracking, and Budget Enforcement&govern.escalation— Human-in-the-Loop Escalation and Governance Handoff&govern.identity— Agent Identity, Verification, and Trust
Skills
- [&] Protocol — Agent Skills
- Skill 01 — Writing Agent Declarations
- Skill 02 — Validation
- Skill 03 — Capability Composition
- Skill 04 — Capability Contracts
- Skill 05 — Generation
- Skill 06 — CLI Reference
- Skill 07 — Integration Patterns
- Skill 08 — Provider Implementation
- Skill 09 — Governance and Provenance
- Skill 10 — Anti-Patterns
Suggested reading order¶
If you’re new to the project, a good path is:
quickstart— get from clone to a workingampersandCLI in minutes, with reproducible command outputarchitecture— understand the protocol’s responsibilities, runtime lifecycle, and end-to-end declaration flowruntime-walkthrough— follow a concrete declaration through validation, composition, provider resolution, and generationpositioning— see where [&] fits relative to MCP, A2A, ACP, and DALIAcompetitive-landscape— understand the structural constraints facing every competitor category in machine cognitiontopology-is-the-authority— why governance must emerge from feedback topology, not be configured on topresearch— understand the ecosystem and research pressures behind the designfaq— get quick answers to common adoption and framing questionsCapability deep dives — explore the six core capability families in detail once the runtime model is clear
skills/SKILLS— hands-on implementation skills registry; start here when you’re ready to build01_DECLARATION→02_VALIDATION→03_COMPOSITION→04_CONTRACTS→05_GENERATION(core workflow)06_CLI_REFERENCE(command reference)07_INTEGRATION_PATTERNS→08_PROVIDER_IMPLEMENTATION(advanced)09_GOVERNANCE_PROVENANCE→10_ANTI_PATTERNS(governance and guardrails)
Core idea¶
A concise framing for the protocol is:
MCP defines how agents call tools.
A2A defines how agents call agents.
[&] defines how capabilities compose into a coherent agent.
The goal is not to replace existing protocols, but to provide a source-of-truth composition layer that sits above runtime wiring and makes agent architecture explicit, portable, and auditable.