Symbol Library

ISA-5.1 gives P&IDs a universal symbol set — any engineer reads any diagram. A&IDs need the same discipline.

Wall Chart

The reference card. Every A&ID code on one screen.

═══════════════════════════════════════════════════════════
  A&ID SYMBOL REFERENCE                         v2.1
═══════════════════════════════════════════════════════════

  AGENTS                        AUTHORITY
  ───────                       ─────────
  HA  Human Agent               [L1] Execute — runs tasks
  DA  Digital Agent              [L2] Decide — routes within scope
  PA  Physical Agent             [L3] Override — halts any L1/L2
  OA  Orchestrator Agent

  SHAPES                        FUNCTION CODES
  ──────                        ──────────────
  ○   Autonomous                A  Alarm (alerts only)
  ○—  Human-in-loop             C  Controller (adjusts)
  □   Orchestrator              G  Gate (pass/fail — halts)
  ◇   External                  V  Validator (scores — passes)
                                M  Monitor (observes)
  INSTRUMENTS                   R  Recorder (logs)
  ───────────                   S  Selector (chooses path)
  Digital (Crypto)              T  Transmitter (sends)
  ST  Settlement Token          CONNECTIONS
  GT  Governance Token          ───────────
  IT  Incentive Token           ───── Value flow
  ID  Identity (ZK)             - - - Signal flow
                                · · · Feedback flow
  Physical (Intercognitive)
  IP  Positioning               CONDITIONS ON LINES
  TS  Time Sync                 ────────────────────
  IS  Sensors                   [P]    Pass
  IM  Maps                      [F]    Fail
                                [T:n]  Time-triggered
  Feedback                      [E:x]  Event-triggered
  VV  Verifiable Value          [Q:>=n] Quality threshold
  LR  Learning & Refinement     ⊗      Override point

  STATE                         FAIL-SAFE
  ─────                         ─────────
  ●  Active                     [FC] Fail-Closed (blocks)
  ○  Dormant                    [FO] Fail-Open (passes last)
  ✕  Failed                     [FR] Fail-Reset (defaults)
  ?  Exploring
  →→ Delegated                   DECISIONS
                                ─────────
  READING A CODE                ◇X  Exclusive (one path)
  ──────────────────            ◇O  Inclusive (one or more)
  [Family]-[Function][##]       ◇+  Parallel (all paths)
  [Family]-D[Type][##]          ◇E  Event (first signal)
                                ◇M  Merge alternatives
  VFL-G01  VFL Gate #1          ◇J  Join parallel flows
  VFL-V01  VFL Validator #1
  VFL-DX01 VFL Decision #1      LOOP TYPES
                                ──────────
  OPT-G02  Optimal Stopping     ↺   Closed loop
  EXP-S01  Explore-Exploit      ↺↺  Cascade loop
  IT-A01   Incentive Alarm       →   Open (no return)
  LR-C01   Learning Controller   ⟳   Learning loop
                                ⇉   Feedforward

═══════════════════════════════════════════════════════════

Agent Types

Replaces P&ID equipment classes. First letter of any agent code.

Code	Agent Type	P&ID Equivalent	Example
HA	Human Agent	Manual Operator	Founder, Sales Rep
DA	Digital Agent	Automated Controller	AI Agent, Swarm
PA	Physical Agent	Robotic Equipment	DePIN Robot, IoT Device
OA	Orchestrator Agent	Supervisory Controller	Nav, Conductor

Agent Shapes

Visual shorthand for agent autonomy level in diagrams.

Shape	Meaning	When to Use
`○`	Autonomous	Runs without human approval
`○—`	Human-in-loop	Requires confirmation before action
`□`	Orchestrator	Routes other agents
`◇`	External	Outside control boundary

Instrument Types

Replaces P&ID instruments. Grouped by domain.

Digital Instruments (Crypto)

Code	Instrument	P&ID Equivalent
ST	Settlement Token	Flow Meter
GT	Governance Token	Control Valve
IT	Incentive Token	Pressure Gauge
ID	Identity (ZK)	Safety Interlock

Physical Instruments (Intercognitive)

Code	Instrument	P&ID Equivalent
IP	Positioning	Level Sensor
TS	Time Sync	Clock
IS	Sensors	Transmitters
IM	Maps	Drawings / P&IDs

Feedback Instruments

Code	Instrument	P&ID Equivalent
VV	Verifiable Value	Quality Analyzer
LR	Learning & Refinement	Adaptive Controller

Function Codes

Second letter declares what the instrument DOES. Same principle as P&ID — FV01 tells you it controls Flow before you read the legend.

Code	Function	What It Does	P&ID Equivalent
A	Alarm	Triggers on threshold, alerts only	High/Low Alarm
C	Controller	Adjusts continuously (PID-like)	PID Controller
G	Gate	Binary pass/fail — halts flow on fail	Safety Interlock
M	Monitor	Observes and records, no control authority	Indicator
R	Recorder	Logs outcomes for feedback loops	Chart Recorder
S	Selector	Chooses between paths or agents	Transfer Switch
T	Transmitter	Sends output without deciding	Transmitter
V	Validator	Scores/transforms without halting — output is quality signal	Analyzer (non-safety)

Code Grammar

Full code format: [Family]-[Function]##

Code	Read As	Meaning
`VFL-G01`	VFL Gate #1	Halts flow if VVFL criteria fail
`OPT-G02`	Optimal Stopping Gate #2	Halts if signal insufficient
`EXP-S01`	Explore-Exploit Selector #1	Chooses channel or path
`VV-R01`	Verifiable Value Recorder #1	Logs settlement outcomes
`LR-C01`	Learning Controller #1	Adjusts agent parameters
`CPD-M01`	Compound Rate Monitor #1	Observes rate, no control
`IT-A01`	Incentive Token Alarm #1	Alerts when below threshold
`IT-G01`	Incentive Token Gate #1	Token required to proceed

The function code splits overloaded families without new top-level codes. IT (Incentive Token) alone covers alarms (IT-A), gates (IT-G), and controllers (IT-C).

Connection Conditions

Add to existing line types (solid/dashed/dotted). Conditions go on the line label.

Notation	Meaning	Example
`[P]`	Gate-conditional — flows on Pass	`VFL-G01 ──[P]──> next stage`
`[F]`	Fail path	`VFL-G01 ──[F]──> recycle`
`[T:n]`	Time-triggered — fires every n	`LR-C01 ──[T:weekly]──> tune`
`[E:event]`	Event-triggered	`ST-T01 ──[E:receipt]──> settle`
`⊗`	Override point — HA can break this flow	`HA[L3] ⊗ VFL-G01`
`[Q:>=n]`	Quality threshold — soft gate, routes by score	`VFL-V01 --[Q:>=70]--> fast track`

Fail-Safe States

What happens when an agent or instrument faults.

Notation	State	Meaning
`[FC]`	Fail-Closed	Blocks all flow on fault
`[FO]`	Fail-Open	Passes last known state on fault
`[FR]`	Fail-Reset	Reverts to default config on fault

Distinction: G (Gate) is a design-time function code — what the instrument does. [FC]/[FO]/[FR] are runtime fault responses — what happens when the instrument itself breaks.

Authority Layer

Agents carry an authority level. Higher overrides lower.

Code	Level	Can Override	Example
L1	Execute	Runs assigned tasks only	`DA[L1]` — worker agent
L2	Decide	Routes and selects within scope	`OA[L2]` — orchestrator
L3	Override	Can halt or redirect any L1/L2	`HA[L3]` — founder

HA[L3] can override VFL-G01. OA[L2] can redirect DA[L1] but not override HA[L3].

State Indicators

Appended to agent codes in brackets.

Symbol	State
`●`	Active
`○`	Dormant
`✕`	Failed
`?`	Exploring
`→→`	Delegated

Decision Types

Where choice happens. Typed decisions replace generic diamonds — every branch declares its semantics.

Symbol	Type	Meaning	When to Use
`◇X`	Exclusive	Choose exactly one path	Approved vs rejected, list vs kanban
`◇O`	Inclusive	Choose one or more paths	Multiple instruments contribute evidence
`◇+`	Parallel	Take all paths at once	Settle value AND update model simultaneously
`◇E`	Event	Path depends on which event arrives first	Sensor signal vs timeout vs external response
`◇M`	Merge	Recombine alternative paths, no waiting	After an exclusive choice resolves
`◇J`	Join	Recombine concurrent paths, wait for all	Arbitration — all evidence collected before ruling

Decision Rules

Put questions inside decisions: "Signals agree?" not "Signal check"
Label every outgoing branch: [P] / [F], Yes / No, or named conditions
Branch type and recombination type must match: ◇X closes with ◇M, ◇+ closes with ◇J
Two exits per decision. If more, chain decisions

Decision grammar: [Family]-D[Type]## — e.g., VFL-DX01 = VFL Exclusive Decision #1

Loop Types

Label on feedback arcs.

Symbol	Loop Type	Meaning
`↺`	Closed	Signal returns to same agent
`↺↺`	Cascade	Signal triggers secondary loop
`→`	Open	Signal exits without return
`⟳`	Learning	Crosses venture boundary — improves the template
`⇉`	Feedforward	Acts on predicted input before arrival

Connection Types

Replaces P&ID line types. How agents and instruments communicate.

Line	Meaning	P&ID Equivalent
Solid	Value flow (tokens, payments)	Physical piping
Dashed	Signal flow (data, decisions)	Signal connection
Dotted	Feedback flow (metrics, learning)	Pneumatic signal

Questions

Can two-letter codes handle the complexity of real-world agent systems, or is the notation already constrained?

The library splits IT (Incentive Token) into IT-A, IT-G, IT-C via function codes. At what point does a single family code represent too many distinct mechanisms?
Which diagram elements from this reference card are never used in practice — and why are they still here?
If someone invents a new instrument type (e.g., a privacy-preserving oracle or a reputation token), where does it fit in this grid?

Next: See Worked Examples — how to read and build diagrams.

Wall Chart​

Agent Types​

Agent Shapes​

Instrument Types​

Digital Instruments (Crypto)​

Physical Instruments (Intercognitive)​

Feedback Instruments​

Function Codes​

Code Grammar​

Connection Conditions​

Fail-Safe States​

Authority Layer​

State Indicators​

Decision Types​

Decision Rules​

Loop Types​

Connection Types​

Questions​