Compiled agent defaults¶

This page shows what a minimal Agent manifest expands to. Read it to see which defaults the runtime applies to the fields you leave out.

The problem¶

A minimal manifest omits most fields. mas-ctl compile fills each omitted field before the runtime sees the manifest. It sets the plugin for every singleton slot (design_pattern, context_manager, assembler). It sets the sub-plugin that one slot composes (context_manager.params.summarizer). It sets every attribute each plugin takes.

A plugin is a unit of behaviour that a manifest selects by name. Three forms give the same runtime behaviour: omit the field, write the plugin name, or write the fully expanded object. See plugin-bindings.md.

This page is a worked example, not a schema. Field-by-field docs are on the pages linked from each block. If a number here looks stale, re-run the command in Regenerating this page and trust its output.

The input: Tutorial 1's minimal manifest¶

docs/tutorials/01-building-an-agent/agent.yaml declares a model, a description, and a system-prompt fragment. It declares nothing else:

apiVersion: mas/v1
kind: Agent

metadata:
  name: qa-agent

spec:
  models:
    - model: gpt-4o

  description: Answer general knowledge questions.
  context:
    intent: "Answer general knowledge questions."
    role: |
      Answer questions clearly and concisely.

The output: `mas-ctl compile agent.yaml`¶

apiVersion: mas/v1
kind: Agent
metadata:
  name: qa-agent
spec:
  models:
  - model: gpt-4o
  description: Answer general knowledge questions.
  context:
    intent: Answer general knowledge questions.
    role: 'Answer questions clearly and concisely.

      '
  design_pattern:
    type: react@v1
    params:
      max_cot_pass: 1
      parallel: true
  context_manager:
    type: summarising
    params:
      keep_turns: 10
      hysteresis_ratio: 0.1
      summarizer: llm
      trimmer:
        reserve_tokens: 2000
        safety_margin_ratio: 0.1
  assembler:
    type: assembler
    params:
      emit_segments: true
      always_reassemble: false

What each block is¶

Block	Plugin (default)	Attributes	Docs
`models[0].context_window`	none	Auto-resolved from the effective model; an unknown model warns and uses `128000`	agent.md · context-management
`design_pattern`	`react@v1` (registry alias `react`)	`max_steps` (dispatch-loop cap), `max_cot_pass`, `parallel`	plugin-bindings.md § design_pattern
`assembler`	`assembler` (`ContextAssemblerPlugin`)	`emit_segments`, `always_reassemble` — builds `messages[]`; not where history policy lives	plugin-bindings.md § assembler · context-assembly.md
`context_manager`	`summarising`	`keep_turns`, `hysteresis_ratio`, `summary_threshold`, `archive`, `trimmer.{max_tokens,reserve_tokens,safety_margin_ratio}`	plugin-bindings.md § context_manager · context-management
`context_manager.params.summarizer`	`llm` (sub-plugin of `summarising`)	`params.model` omitted → summarizer slot (Agent/MAS/`experiment.models.summarizer`) else agent's primary model. Compile does not invent a cheaper summarizer.	plugin-bindings.md § summarizer · summarization.md

Every block is a real registered plugin. The runtime resolves type: react@v1, type: summarising, type: assembler, and type: llm through the same registry as an explicit choice. No hidden "if omitted, do X in code" branch exists. The default is a binding.

Defaults come from two places:

The singleton slots (model, design_pattern, context_manager, assembler) come from the built-in runtime/src/mas/runtime/defaults.yaml of mas-runtime.
Other slots and sub-plugins (summarizer, tool_provider, llm_provider, agent_comm, hitl_contract, user_io_contract) come from the defaults: map in library-standard/library.yaml.

You can override the four singleton keys per workspace in config.yaml defaults:. No agent manifest changes. See config.yaml, defaults.

Regenerating this page¶

The numbers above drift as defaults change. Reproduce them from any manifest. The expansion works on your own agents, not only the tutorial:

cd docs/tutorials/01-building-an-agent
mas-ctl compile agent.yaml --no-header

Add -o overlays/<file>.yaml (repeatable) to fold overlays in first. An overlay is a small YAML file merged on top of a manifest. See the compile command reference. To see what a manifest sets versus package defaults, add --no-defaults and diff.