Cline (subagent / task delegation)

What is it

This skill teaches your agent to use an agent from another vendor as a subagent.

Almost every coding agent has a headless mode. Headless mode runs the agent from the terminal with one command and returns the answer to stdout. This skill gives the command pattern for one such agent, and the protocol to transfer enough context with the task.

You stay the main agent. You keep the plan, the decisions and the conversation with the user. The subagent does one bounded task and reports back.

When to delegate

• The user asks for it. The user names another agent, or asks for a second opinion.
• Large or multi-step work. The task covers several files, phases or checkpoints.
• Code review with a fresh mind. Another agent reviews the work with a different lens and no memory of the decisions that produced it.
• Planning that needs different ideas. A second agent proposes options that you did not consider.
• An internal council. Several subagents answer the same question, and you compare the answers.
• Deep research. The other CLI has web search, web extraction or browser automation.
• Background investigation. A long task runs in the background while you continue in the foreground.

When not to delegate

• Small or single-step tasks. One or two edits, or a short explanation, are faster in this thread.
• Tight feedback loops. The user wants quick back-and-forth in one conversation.
• Secrets or policy-sensitive work. Do not pipe credentials into a subagent. Redact first.
• Context you already hold. Repeating the whole plan in a prompt adds no value.
• Low return on investment. If writing the handoff costs more than doing the edit, do the edit.
• Work that needs high precision and full judgement. A subagent without your context will break a task that depends on a detail only this session knows.

Delegation and context transfer protocol

An isolated subagent saves tokens, but it splits the story. The subagent does not see this conversation. It has no memory of the goal you agreed with the user, the decisions you already made, or the paths you agreed not to touch. A poor handoff causes misread tasks, wrong assumptions about the stack or the style, and wasted edits.

Treat every call as stateless delegation: the subagent keeps nothing between calls, so each command must carry its own state. A good handoff happens when you keep these practices in mind:

• Shared state handoff. The prompt carries the original goal, the decisions already made, and the explicit scope, to bridge the subagent's missing session history.
• Contextual preservation. The high-volume work stays in the isolated process, so the bulk never enters this conversation and no "split story" forms from missing history.
• Result reconciliation. What comes back is folded into this thread afterwards, so there is a single source of truth.

Write the prompt as a transfer of shared state, not as a title. Include all six fields:

Prefer sequential delegations with explicit carry-over. Parallel runs diverge unless every run gets the same briefing.

Run the subagent in the mode that does the work without asking for approval. Headless mode has nobody to answer a permission prompt. Any mode that stops to ask will stall, or return an empty answer with a success exit code. Each CLI names this mode differently — take the flag from the vendor card below.

Never call a subagent in plan mode. Many CLIs have a plan or read-only mode. That mode makes the other agent write a plan for itself, which is not what you asked for: you want its work or its answer, and you keep the planning. Plan mode also waits for someone to approve that plan, so the run comes back with nothing. If you want no file changes, keep the auto-approving mode and write "report only, no edits" in the Output field. Do not use plan mode to make a run read-only.

After the subagent returns:

• Report to the user. Give a short summary. Do not paste long logs unless the user asks.
• Reconcile the context. Record the decisions it made, the files it changed, and the open risks, so this session stays the single source of truth.

CLI failure modes

Every vendor has its own terminal rules. A headless run fails quietly more often than it fails loudly.

• Wrap the call in an external timeout. A headless CLI can stall before its own timeout starts.
• Exit code 0 is not success. If stdout is empty, treat the run as failed and read stderr. A permission the CLI could not ask for, and a prompt that never arrived, both look like success.
• Never carry a flag habit from one CLI to another. The same short flag means different things in different tools. In OpenCode, -p is --password: passing a prompt to it empties the message and the run waits on stdin forever. Confirm every flag against the CLI's own --help.
• An unrecognized-flag error means this skill is stale, not that the task is impossible. Read --help, continue with the flags that exist, and tell the user which line in this file is wrong.

Vendor card

Binary and prompt form

• Binary: cline
• Install: npm i -g cline (vendor CLI overview page).
• Prompt form: positional. cline "prompt" — the usage line is cline [options] [command] [prompt], and the argument help reads "Your prompt. Default to start in act mode with auto-approve enabled."
• The verified trap: -p is --plan, not "print" or "prompt". In several other CLIs -p passes the prompt; here it switches the run into plan mode, which this skill forbids. Writing cline -p "GOAL: ..." does not pass a prompt — it makes the other agent plan for itself and return nothing useful. Pass the prompt positionally, with no flag. Note also that -p means something different again inside cline auth, where it is --provider.
• Two undocumented gotchas, both found by running the binary:
  1. A single-token prompt is rejected. cline "hi" fails with error: Unknown command or unquoted prompt: hi and exit 1, even though it was quoted. Any prompt containing whitespace works — which a real six-field handoff always does, so this only bites on a smoke test.
  2. Piping alone is not enough. echo "..." | cline --json fails with JSON output mode requires a prompt argument or piped stdin. Piping plus a positional prompt works. Always pass the prompt positionally, even when you also pipe content in.

Headless and output flags

The interactive interface is opt-in through -i/--tui, so a plain call stays non-interactive. Do not pass -i from a script.

Approvals and permissions

Cline already auto-approves. --auto-approve <boolean> carries a documented default of true, and the positional prompt help states the run starts "in act mode with auto-approve enabled". So a plain cline "prompt" does the work without stopping to ask, and no extra flag is needed.

Pass --auto-approve false only when the user explicitly asks for a run that stops at every tool. That is not useful headless, because nobody can answer. Note the default flips to false in ACP mode, and that when stdin/stdout is not a TTY, calls that still require approval are denied.

To restrict which shell commands are allowed, use the environment rather than a flag: CLINE_COMMAND_PERMISSIONS='{"allow":["npm *"],"deny":["rm -rf *"]}'. Deny wins over allow.

Never pass -p/--plan. Plan mode makes the other agent write a plan for itself and wait for someone to approve it, so the run returns nothing. For a no-edit run, keep the default act mode and write "report only, no edits" in the Output field of the handoff.

Models and how to list them

cline auth configures the provider and the model, and it accepts -p/--provider <id>, -m/--modelid <id>, -k/--apikey, and -b/--baseurl. Inspect the result with cline config.

Per run, select with -P/--provider <id> and -m/--model <model-id>. The default provider is cline. This build ships no command that prints a list of model identifiers — check cline auth --help and the vendor documentation, and prefer whatever the user names. For capability and price comparisons, check Artificial Analysis.

Command pattern

cline "GOAL: [goal] | DECISIONS: [decisions] | SCOPE: [absolute paths] | CONSTRAINTS: [constraints] | VERIFICATION: [test_command] | OUTPUT: [format]" \
  --cwd /absolute/path/to/repo --json --timeout 900 2>&1

--timeout defaults to 0, which means the run has no deadline of its own. Set it, or run the call in the background and watch the log.

Prompt examples

• Implement: cline "GOAL: [goal] | DECISIONS: [decisions] | SCOPE: [absolute paths] | VERIFICATION: [test_command] | OUTPUT: files changed" --cwd /abs/repo --timeout 900
• Review: cline "GOAL: Review [scope] for [concerns] | CONSTRAINTS: do not edit any file | OUTPUT: findings with severity" --cwd /abs/repo --json
• Investigate: cline "GOAL: Map how [feature] works | SCOPE: [absolute paths] | CONSTRAINTS: do not edit any file | OUTPUT: file:line map" --cwd /abs/repo --json

Docs and reference

• Flags, models, approvals, skills and paths: reference.md
• Vendor documentation: https://docs.cline.bot/cli/cli-reference
• Checked on 2026-11-05 against the official documentation and the 3.0.63-3.0.74 release notes. Not run against an installed binary; the flag details come from a cline 3.0.62 --help run on 2026-09-21. The latest npm version is 3.0.74.