Reference

$ fisk-ai run --config nats.yaml "report on the ORDERS stream"

# agent.yaml - drive the NATS CLI as an agent

application_path: /usr/local/bin/nats

llm:
  model: claude-sonnet-4-6
  budget:
    max_tokens: 200000
    max_iterations: 50
    call_timeout: 120s

system_prompt: |
  You manage NATS JetStream Streams using tools.

# agent.yaml - answer questions from a local knowledge base, no wrapped app

llm:
  model: claude-sonnet-4-6

system_prompt: |
  You answer questions using the knowledge_search tool over the indexed docs.

harness:
  knowledge:
    enabled: true

# The name of the agent. Used in discovery and reused as a NATS queue
# group, so it must contain only letters, digits, "-" or "_". If you
# leave it out it defaults to the application binary's base name, or to
# "fisk-ai" when no application_path is set; set it explicitly when the
# derived name carries a dot, a space, or other characters, which are
# rejected, or to keep memory/knowledge stores separate between agents.
identity: nats

# Path to the Fisk application binary to introspect and run. OPTIONAL.
# When set, the binary is introspected once at startup to obtain its
# command tree and per-command JSON schemas. Leave it out to run an agent
# on the built-in tools (knowledge, memory, human_in_the_loop) and any
# remote tools alone, with no wrapped application. Required only for "a2a"
# mode, which serves the wrapped application's tools.
application_path: /usr/local/bin/nats

# The system prompt describing what the agent should do. REQUIRED for a
# "run", ignored by "mcp" and "a2a" mode. Think of it as a one-file SKILL:
# describe the goals and give broad guidance.
system_prompt: |
  You manage NATS JetStream Streams using tools.

# Keep only the commands whose tool name or tag matches. When "include" is
# present, a command must match it to be exposed.
include:
  # Regular expressions matched against the tool name: the command path
  # joined with underscores, so the "stream info" command is "stream_info".
  tools:
    - ^stream_
    - ^consumer_info$
  # Match commands by fisk tag. An empty string "" matches untagged
  # commands. The reserved ai:deny tag is always active and can never be
  # included back in.
  tags:
    - scope:read

# Remove matching commands. Applied as a filter: a command that matches
# "exclude" is dropped even if "include" allowed it.
exclude:
  tools:
    - ^stream_rm$
  tags:
    - scope:system

llm:
  # The model identifier. REQUIRED. Accepts any value the Anthropic API
  # accepts; the well-known identifiers are listed under "Models" below.
  model: claude-sonnet-4-6

  # Bounds on a single run so the agent loop cannot spend without limit.
  # The run stops with a summary once any of these is reached, whether or
  # not the task is complete.
  budget:
    # Cumulative token spend cap for the run. Default 200000.
    max_tokens: 200000
    # Maximum agent loop iterations. Default 50.
    max_iterations: 50
    # Per-call timeout as a Go duration string, for example "60s" or
    # "2m". Default "120s".
    call_timeout: 120s

  # Controls whether the model exposes its reasoning. Off by default; when
  # off, no thinking is requested and the model uses its default behavior.
  thinking:
    # When true, asks the model to think and surfaces its reasoning
    # separately from the answer (thought-bubble lines on stderr in shell
    # mode, folding blocks in the TUI). Older models that predate adaptive
    # thinking (Sonnet 4.5, Haiku 4.5) reject it, so leave it off for those.
    enabled: false

  # When true, disables Anthropic prompt caching for the run. Left off,
  # Fisk AI caches the stable prefix of each request to lower cost and
  # latency on multi-turn runs.
  no_prompt_cache: false

harness:
  # Opt-in built-in tools that let the model ask the operator a question
  # at the terminal (agent mode only).
  human_in_the_loop:
    # When true, offers the model the ask_human_confirm, ask_human_select,
    # and ask_human_input tools. Off by default.
    enabled: true

  # Command tags that, in addition to the always-on ai:confirm tag, gate a
  # command behind operator approval before it runs. Matching is exact, not
  # a regex, and additive to ai:confirm. An entry that matches no loaded
  # command is reported as a warning at startup.
  confirm_tags:
    - impact:rw

  # A hard off switch for the full-screen terminal UI: the agent always
  # uses line-by-line output, even on an interactive terminal, and the
  # command line cannot turn the UI back on. Use the --no-tui flag for a
  # one-off run instead. Negative switch, no effect in the line UI.
  no_tui: false

  # The full-screen UI rings the terminal bell each time a run blocks
  # waiting on you (an approval gate or an ask_human_* prompt). On by
  # default; set true to silence it. Negative switch, no effect in the
  # line UI.
  no_bell: false

  # Opt-in built-in key/value store that survives across runs (agent mode
  # only).
  memory:
    # When true, offers the model the memory_list, memory_read,
    # memory_write, and memory_delete tools. Off by default.
    enabled: true
    # The store implementation. Defaults to "file", which keeps each
    # memory in a markdown file under a directory; it is the only backend
    # today.
    backend: file
    # By default the stored keys and descriptions are injected into the
    # system prompt at run start so the model knows what it has saved. Set
    # true to keep the store's contents out of the prompt. Negative switch.
    no_index: false
    # Backend-specific settings. For the "file" backend: "directory", the
    # path memory files live under, defaulting to "memory/<identity>".
    options:
      directory: memory

expose:
  agent:
    # The opt-in block that enables MCP serving. Must be present, even if
    # empty ({}), for "fisk-ai mcp" to start.
    mcp:
      # Default listen port, used when neither --port nor the
      # FISK_AI_MCP_PORT environment variable is set. Default 8080.
      port: 8080

      # Free-text guidance sent to clients when they connect. A client may
      # pass it to the model as a hint about how to use the server, a good
      # place for orientation the terse per-tool descriptions cannot carry.
      instructions: |
        These tools wrap the NATS CLI. Prefer stream_info before
        stream_edit, and treat all subjects as relative to the FOO account.

      # How confirmation-gated commands (ai:confirm or a confirm_tags tag)
      # behave when the connected client cannot be asked through
      # elicitation:
      #   auto   - default; ask clients that can elicit, run ungated for
      #            clients that cannot
      #   always - ask clients that can elicit, refuse for clients that
      #            cannot be asked
      #   never  - never ask, run gated commands ungated, delegating
      #            approval to the client's own UI
      confirm_over_mcp: auto

    # Optional: narrow the served set further, within the top-level
    # include/exclude selection. With neither, every selected command is
    # served (subject to the tag rules). Same regex-over-tool-name and tag
    # matching as the top-level filters.
    tools:
      include:
        tools:
          - ^stream_
      exclude:
        tools:
          - ^stream_rm$

# Name of a NATS context (as managed by "nats context" and resolved by
# jsm.go) used to connect to NATS. REQUIRED when remote_tools is set or
# when running "fisk-ai a2a".
nats_context: ngs

expose:
  agent:
    # When true, "fisk-ai a2a" serves this agent's tools over NATS. Opt-in:
    # without it, "fisk-ai a2a" refuses to start. Like MCP mode, serving
    # needs only application_path, identity, nats_context, and the tool
    # selection. Confirmation-gated commands are never served, since there
    # is no operator to approve them.
    agent_to_agent: true

# Import tools from one or more remote fisk-ai agents over NATS and expose
# them to this agent alongside its local tools.
remote_tools:
  - # The remote agent's identity (also the NATS subject key). REQUIRED.
    name: nats
    # A prefix for the imported tool names. Applied only when a bare name
    # would clash with a local tool or another remote's tool. Defaults to
    # "name".
    alias: nats
    # Select which of the remote agent's tools to import, matched against
    # the tool name only. A "tags" filter cannot be honored, since
    # discovery does not carry tags, and an exclude-by-tag is rejected at
    # startup.
    include:
      tools:
        - ^stream_
    exclude:
      tools:
        - ^stream_rm$