A2A agents

Send messages to A2A agents (Agent2Agent protocol) as another agent sends them, and check what they answer: the tasks they run, with their states and their artifacts, as they answer or as they stream.

Given the parcels a2a agent with the following properties:
  | url | http://localhost:8400 |
When a message is sent to the parcels a2a agent:
  """
  Where is PX-A2A-9201?
  """
Then the parcels a2a agent's task is completed
And the parcels a2a agent's answer contains 'out for delivery'

• The card is the contract: it is read at /.well-known/agent-card.json (or from a file), checked for what A2A 1.0 requires, and says how to reach the agent: JSON-RPC, HTTP+JSON or gRPC.
• A conversation: a message starts one; a reply continues the agent’s last task, which is how a task that asks for input (input-required) gets it.
• Streams belong to the scenario, which ends them when it ends. The checks wait (10 seconds, or within {duration}) for what the stream has not sent yet.
• States are written as people say them: submitted, working, completed, input-required, auth-required, failed, canceled, rejected.
• Secrets stay secret: ${env:..} values in the properties are masked in logs and failures, and ${token:..} names a token of the scenario.

Add it to a project with axx pack add a2a.

Steps

a2a.agent

Given the {word} a2a agent with the following properties:
  | property | value |

The table may start with the row naming its columns, as above, or go straight to its rows.

Register an A2A agent under a name: its card is read and checked for what A2A 1.0 requires, and says how to reach it (JSON-RPC, HTTP+JSON or gRPC).

Parameter	Takes	For example
{word}	one word, with no spaces	parcels, PX-4101

Property	Takes	Values	Default
url	the agent’s URL; its card is read at /.well-known/agent-card.json on its origin
card	the agent’s card, when it is not there: a file of the project, or a URL
transport	how to reach the agent, among the interfaces its card lists	JSONRPC, HTTP+JSON, GRPC	the card's first
header.<name>	a header sent with every request, such as header.Authorization
timeout	how long a call may take, like 10s		30s
push url	where the agent sends its tasks’ updates (a webhook, such as a WireMock the mock pack checks)
push token	the token the agent sends with them, for the webhook to check

A url or a card is required. Values are expanded (${env:..}, ${sys:..}, ${token:..}); what ${env:..} references expand to is masked everywhere.

Example:

Given the parcels a2a agent with the following properties:
  | url | http://localhost:8400 |
Given the carrier a2a agent with the following properties:
  | url                  | https://agents.carrier.example |
  | transport            | HTTP+JSON                      |
  | header.Authorization | Bearer ${token:carrier}        |

Since 0.1.5.

a2a.card

Then the {word} a2a agent's card has the following properties:
  | property | value |

The table may start with the row naming its columns, as above, or go straight to its rows.

Check the agent’s card: what another agent reads to find out what it does and how to reach it.

Parameter	Takes	For example
{word}	one word, with no spaces	parcels, PX-4101

A row is a path into the card (name, capabilities.streaming, skills[0].id) and its value.

Example:

Then the parcels a2a agent's card has the following properties:
  | name                   | Parcels agent |
  | capabilities.streaming | true          |

Since 0.1.5.

a2a.skill

Then the {word} a2a agent has the {word} skill

Check that the agent’s card lists a skill, by its id.

Parameter	Takes	For example
{word}	one word, with no spaces	parcels, PX-4101

Example:

Then the parcels a2a agent has the track-parcel skill

Since 0.1.5.

a2a.send

When a message is sent to the {word} a2a agent:
  """
  ...
  """

Send the doc string as a text message, which starts a conversation, and wait for the agent’s answer: a reply, or a task that ended or waits for input.

Parameter	Takes	For example
{word}	one word, with no spaces	parcels, PX-4101

Example:

When a message is sent to the parcels a2a agent:
  """
  Where is PX-A2A-9201?
  """

Since 0.1.5.

a2a.send.file

When the {filepath} message is sent to the {word} a2a agent

Send the message of a file of the project, an A2A message in JSON (its parts: text, data, files), which starts a conversation, and wait for the agent’s answer.

Parameter	Takes	For example
{filepath}	a file of the project: a path relative to the feature file’s directory, the resources directories or axx.yaml’s directory (looked for in that order), or an absolute path, quoted when it has a space	seeds/parcels.yaml, kafka/scan-delivered.json
{word}	one word, with no spaces	parcels, PX-4101

Example:

When the a2a/hold-request.json message is sent to the parcels a2a agent

Since 0.1.5.

a2a.stream

When a message is streamed to the {word} a2a agent:
  """
  ...
  """

Send the doc string as a text message, which starts a conversation, and take the agent’s answer as it streams: the checks read its updates as they come. The stream belongs to the scenario, which ends it when it ends.

Parameter	Takes	For example
{word}	one word, with no spaces	parcels, PX-4101

Example:

When a message is streamed to the parcels a2a agent:
  """
  Where is PX-A2A-9203?
  """

Since 0.1.5.

a2a.reply

When a reply is sent to the {word} a2a agent:
  """
  ...
  """

Send the doc string as a text message that continues the agent’s last task: how a task that asks for input (input-required) gets it. Wait for the agent’s answer.

Parameter	Takes	For example
{word}	one word, with no spaces	parcels, PX-4101

Example:

When a reply is sent to the parcels a2a agent:
  """
  2026-10-05
  """

Since 0.1.5.

a2a.cancel

When the {word} a2a agent is asked to cancel its task

Ask the agent to cancel its last task; check that it did with the {word} a2a agent's task is canceled. An agent that will not (a task that ended) fails the step with its error.

Parameter	Takes	For example
{word}	one word, with no spaces	parcels, PX-4101

Example:

When the parcels a2a agent is asked to cancel its task

Since 0.1.5.

a2a.state

Then [[within {duration} ]]the {word} a2a agent's task is {word}

Check the state of the agent’s last task: submitted, working, completed, input-required, auth-required, failed, canceled or rejected.

• The check waits for a task still at work (10 seconds, or within {duration}), and fails at once for a task that ended or waits for input in another state.

Parameter	Takes	For example
{duration}	a duration in seconds (s) or minutes (m)	5s, 2m
{word}	one word, with no spaces	parcels, PX-4101

Variants, the parts in [[...]] said or left out:

• the {word} a2a agent's task is {word}
• within {duration} the {word} a2a agent's task is {word}

Example:

Then the parcels a2a agent's task is input-required
Then within 30s the parcels a2a agent's task is completed

Since 0.1.5.

a2a.answer

Then the {word} a2a agent's answer contains {string}

Check that the agent’s answer has a text: its reply, or its task’s status message and artifacts. It waits for a task still at work.

Parameter	Takes	For example
{word}	one word, with no spaces	parcels, PX-4101
{string}	text in double or single quotes, which the step leaves out	"Get a quote", 'Express'

Example:

Then the parcels a2a agent's answer contains 'out for delivery'

Since 0.1.5.

a2a.artifact

Then the {word} a2a agent's task has an artifact where:
  | property | value |

The table may start with the row naming its columns, as above, or go straight to its rows.

Check that an artifact of the agent’s last task has the table’s properties: name, description, text (its text parts), data (its first data part: data.status) and parts. It waits for a task still at work.

Parameter	Takes	For example
{word}	one word, with no spaces	parcels, PX-4101

A row is a path into the artifact, and its value.

Example:

Then the parcels a2a agent's task has an artifact where:
  | name        | parcel-status    |
  | data.status | OUT_FOR_DELIVERY |

Since 0.1.5.

a2a.update

Then [[within {duration} ]]the {word} a2a agent's stream received an update where:
  | property | value |

The table may start with the row naming its columns, as above, or go straight to its rows.

Check that the stream of the message streamed last sent an update with the table’s properties.

• A status update has kind status, its state and its message; an artifact update has kind artifact and its artifact (artifact.name, artifact.text, artifact.data.status…).
• The check waits (10 seconds, or within {duration}), and fails at once when the stream has ended.

Parameter	Takes	For example
{duration}	a duration in seconds (s) or minutes (m)	5s, 2m
{word}	one word, with no spaces	parcels, PX-4101

A row is a path into the update, and its value.

Variants, the parts in [[...]] said or left out:

• the {word} a2a agent's stream received an update where:
• within {duration} the {word} a2a agent's stream received an update where:

Example:

Then the parcels a2a agent's stream received an update where:
  | state   | working                  |
  | message | Looking up PX-A2A-9203   |

Since 0.1.5.