Packet Format¶

The AXL packet is the atomic unit of agent communication. Every message, command, signal, and payment flows as a single pipe-delimited packet string.

Template¶

Every AXL packet follows this structure:

@rosetta_url|π:ID:SIG:GAS|T:timestamp|S:DOMAIN.TIER|fields...|FLAGS

Anatomy¶

A packet is composed of four sections: preamble, selector, body, and flags.

1. Preamble¶

The preamble contains three required segments:

Segment	Format	Purpose
Rosetta link	`@rosetta_url`	Points to the Rosetta spec the packet conforms to. Enables self-bootstrapping - any agent that receives this packet can fetch the spec and learn the grammar.
Payment proof	`π:AXL_ID:SIG:GAS`	Cryptographic proof-of-payment. See Payment Proof.
Timestamp	`T:unix_epoch`	Integer Unix timestamp. Provides total ordering.

2. Selector¶

S:DOMAIN.TIER

The selector declares the domain (one of 10 namespaces) and the tier (severity or priority level). See Domains for the full list.

Tiers are domain-dependent but generally follow: CRITICAL, HIGH, MEDIUM, LOW, INFO.

3. Body Fields¶

Body fields are pipe-delimited key:value pairs. The keys and their order are defined by the domain schema. Values carry type determinatives - sigil prefixes that declare the value's type:

target:db-primary|status:!DOWN|metric:latency|value:%312.5|threshold:#100|action:failover

See Type System for the full set of determinatives.

4. Flags¶

Zero or more trailing flags appear at the end of the packet. Flags are bare uppercase tokens - they carry no value, only presence.

LOG|STRM|ACK

See Flags for all six flags.

Examples¶

OPS - Critical Infrastructure Alert¶

@https://axlprotocol.org/rosetta|π:axl_7f3a:ed25519_sig_abc:0.001|T:1719422400
|S:OPS.CRITICAL|target:db-primary|status:!DOWN|metric:latency|value:%312.5
|threshold:#100|action:failover|LOG

Reads as: "Database db-primary is asserted DOWN. Latency is 312.5ms against a threshold of 100ms. Action: failover. Log this event."

COMM - Inter-Agent Request¶

@https://axlprotocol.org/rosetta|π:axl_9b2c:ed25519_sig_def:0.0005|T:1719422500
|S:COMM.HIGH|from:@agent-alpha|to:@agent-beta|intent:REQUEST
|detail:need security audit on repo frontend-v2|ACK

Reads as: "Agent alpha requests agent beta to perform a security audit on frontend-v2. Acknowledge receipt."

SIG - Trading Signal¶

@https://axlprotocol.org/rosetta|π:axl_4e1d:ed25519_sig_789:0.002|T:1719423000
|S:SIG.HIGH|asset:$ETH|price:$3450.00|direction:!LONG|pattern:ascending_triangle
|confidence:%0.87|SIG

Reads as: "ETH at $3,450.00, asserting LONG based on ascending triangle pattern with 87% confidence."

DEV - Code Review Result¶

@https://axlprotocol.org/rosetta|π:axl_c8f2:ed25519_sig_456:0.001|T:1719423100
|S:DEV.MEDIUM|repo:backend-api|branch:feat/auth-refactor|status:!PASS
|action:merge|author:@dev-agent-3|confidence:%0.92|R_risk:%0.15|LOG

Reads as: "Repo backend-api, branch feat/auth-refactor asserted PASS. Recommended action: merge. Risk score 15%."

Parsing Rules¶

Split on | (pipe) to extract segments.
First segment starting with @ is the Rosetta link.
Segment starting with π: is the payment proof.
Segment starting with T: is the timestamp.
Segment starting with S: is the selector; split on . for domain and tier.
Remaining key:value pairs form the body.
Bare uppercase tokens at the end are flags.

Validity¶

A packet is valid if and only if:

It contains a Rosetta link, payment proof, timestamp, and selector.
The domain in the selector is one of the 10 recognized domains.
All required fields for that domain are present.
All typed values carry correct determinatives.