captp

# CapTP: Capability Transfer Protocol **Trit**: 0 (ERGODIC - transports capabilities without amplification) **Color**: #46F27F (Coordinator stream) **Source**: Spritely Goblins (codeberg.org/spritely/goblins) --- ## Overview CapTP (Capability Transfer Protocol) enables distributed object programming with capability security. Objects can live anywhere on the network; CapTP abstracts location so programmers focus on object interaction, not protocol architecture. **Core principle**: Capabilities are unforgeable references. You can only invoke what you've been given. --- ## Key Concepts ### Vats (Actor Containers) ```scheme ;; Guile Goblins (define vat (spawn-vat)) (define greeter (vat-spawn vat ^greeter)) ``` | Concept | Description | Trit Mapping | |---------|-------------|--------------| | **Vat** | Transactional actor container | 0 (ergodic boundary) | | **Actor** | Encapsulated object with behavior | +1 (generative) | | **Capability** | Unforgeable reference | -1 (constraining) | ### Promise Pipelining ```scheme ;; Don't wait for result - pipeline through promises (<- (<- alice 'get-friend) 'greet "Hello") ``` Reduces round-trips: send message to promise, network resolves. ### Sturdy vs Live References | Reference | Persistence | Use Case | |-----------|-------------|----------| | **Live** | Session only | Active communication | | **Sturdy** | Survives restart | Reconnection, storage | --- ## CapTP Message Types ``` op:deliver-only → Fire-and-forget message op:deliver → Message expecting response op:pick → Select from multiple promises op:abort → Cancel pending operation op:listen → Subscribe to updates op:gc → Garbage collection hint ``` --- ## GF(3) Triads ``` # Core CapTP Bundle keychain-secure (-1) ⊗ captp (0) ⊗ gay-mcp (+1) = 0 ✓ [Secure Transport] shadow-goblin (-1) ⊗ captp (0) ⊗ agent-o-rama (+1) = 0 ✓ [Distributed Actors] polyglot-spi (-1) ⊗ captp (0) ⊗ pulse-mcp-stream (+1) = 0 ✓ [Cross-Lang Objects] temporal-coalgebra (-1) ⊗ captp (0) ⊗ koopman-generator (+1) = 0 ✓ [State Observation] # Goblins Integration three-match (-1) ⊗ captp (0) ⊗ gay-mcp (+1) = 0 ✓ [Colored Capabilities] sheaf-cohomology (-1) ⊗ captp (0) ⊗ operad-compose (+1) = 0 ✓ [Compositional] ``` --- ## Implementation Bridge ### Mapping to Our Goblins | Spritely | Our System | Function | |----------|------------|----------| | `spawn-vat` | `SplitMixTernary.new(seed)` | Create isolated generator | | `<-` (send) | `next_color!` | Advance state, get result | | `$` (call) | `color_at(idx)` | Synchronous access | | Sturdy ref | `(seed, index)` tuple | Reconstructable reference | | Promise | Derivation chain | Future state determined by seed | ### Ruby Integration ```ruby require 'captp' # Create vat (generator with transactional boundary) vat = CapTP::Vat.new(seed: 0x42D) # Spawn actor (color stream) actor = vat.spawn(:color_stream) # Send message (advance stream) promise = actor.send(:next_color) # Pipeline (derive without waiting) result = actor.send(:palette, 5).then { |colors| colors.map(&:hex) } ``` ### Scheme Integration (Hoot target) ```scheme (use-modules (goblins) (goblins actor-lib cell)) ;; Define actor constructor (define (^color-stream bcom seed) (define idx (spawn ^cell 0)) (lambda (method . args) (case method ((next-color) (let ((i ($ idx))) ($ idx (+ i 1)) (color-at seed i))) ((palette) (map (lambda (i) (color-at seed i)) (iota (car args))))))) ;; Spawn in vat (define stream (spawn ^color-stream 1069)) (<- stream 'next-color) ;; => promise of color ``` --- ## Netlayers | Layer | Transport | Use Case | |-------|-----------|----------| | **Tor Onion** | .onion addresses | Anonymous, censorship-resistant | | **TCP Direct** | IP:port | Local network, low latency | | **WebSocket** | wss:// | Browser-based (Hoot target) | | **NATS** | nats:// | High-throughput pub/sub | | **Tailscale** | 100.x.y.z | Mesh VPN, zero-config | --- ## Security Model ### Principle of Least Authority (POLA) ``` You can only: 1. Use capabilities you were given 2. Create new objects (that you then have caps to) 3. Introduce objects you have caps to, to each other ``` ### Attenuation ```ruby # Full capability full_stream = vat.spawn(:color_stream, seed: 0x42D) # Attenuated: read-only, no advance read_only = full_stream.attenuate(:color_at) # Attenuated: limited palette size limited = full_stream.attenuate(:palette, max: 10) ``` --- ## Commands ```bash just captp-vat seed=1069 # Create vat with seed just captp-spawn actor_type # Spawn actor in vat just captp-send actor method # Send message just captp-pipeline expr # Pipeline expression just captp-sturdy actor # Get sturdy reference ``` --- ## Related Skills | Skill | Relation | |-------|----------| | **localsend-mcp** | P2P file transfer via CapTP-like protocol | | **tailscale-file-transfer** | Mesh VPN netlayer | | **keychain-secure** | Credential capabilities | | **shadow-goblin** | Validates capability boundaries | | **agent-o-rama** | Generates actor proposals | --- ## References - [Spritely Goblins](https://spritely.institute/goblins/) - [Racket Goblins Docs](https://docs.racket-lang.org/goblins/) - [Heart of Spritely Whitepaper](https://files.spritely.institute/papers/spritely-core.html) - [Hoot: Scheme on WebAssembly](https://spritely.institute/hoot/) - [E Language (historical)](http://erights.org/) --- **Skill Name**: captp **Type**: Distributed Object Protocol **Trit**: 0 (ERGODIC) **GF(3)**: Transports capabilities without amplification **Invariant**: Capabilities unforgeable, only invoke what you're given ## REPL atlas Part of: `repl-commons` (REPL-using skills intermix). ## ACP atlas Part of: `acp-commons`.