Tools

Every logging tool takes summary, uses, session, and agent. The table under each tool lists only the parameters it adds. The six logging tools are marked as writes that change nothing outside HALO, and the three reading tools as read-only.

Shared parameters

Parameter	Type	Default	Meaning
summary	string, required		What happened, in a few words, without secrets or raw personal data.
uses	array of ids	[]	Earlier events this step relied on, such as ["e3", "e7"].
session	string	the MCP session	A label for the conversation or wake-up.
agent	string	--agent, then the client’s name	The agent’s name.

Logging tools

halo_observe

Sensing: something the agent takes in now. Include an earlier action in uses when that action made the agent look.

halo_remember

Memory: something the agent keeps for later interactions. Include what it keeps in uses: an observation, an action, or an outcome.

halo_recall

Memory: the agent looks up something it kept earlier. Include the remember events it retrieved in uses.

halo_act

Action: something the agent does for the user, or a decision to stay silent.

Parameter	Type	Default	Meaning
trigger	request or self, required		request if the user asked for it or set it up, including steps inside a run the user requested or scheduled. self only if nothing the user asked or scheduled started it and the agent decided on its own whether to act
form	silence, communication, preparation, or execution	communication	what kind of action it was

halo_outcome

Sensing: how one of the agent’s earlier actions went.

Parameter	Type	Default	Meaning
about	event id, required		the earlier act event the outcome is about

halo_revise

Mechanism: a durable change to how the agent works, which later runs reuse.

Parameter	Type	Default	Meaning
target	string, required		what changed: a prompt, rule, skill, schedule policy, or similar
made_by	agent or user, required		who made the change
governance	approved, bounded, or none, required		whether the user approved it, it stays within limits the user set, or neither

Reply

A logging tool replies with the new event, or with an error that says how to fix the call:

{ "id": "e5", "agent": "demo", "session": "day2", "note": "Logged e5 (Action, act). Channels: S→A, M→A." }

{ "error": "unknown event id(s) e42 for agent 'demo'; call halo_trace to see the ids of your earlier events" }

Reading tools

halo_trace

Lists the agent’s recent events with their ids, so later steps can name them.

Parameter	Type	Default
limit	integer from 1 to 200	20
session	string, empty for all	""
agent	string	as above

e4 [day2] act: reminded at 9:30 (uses e3) {trigger=self, form=communication}

halo_report

The diagnosis of the agent’s trace, or of one session, as Markdown. Report describes its sections.

halo_guide

Returns the instructions for agents, the same text the server sends as its MCP instructions. It takes no parameters.