Customization

Configuration Files

Swival supports persistent settings through TOML config files at two levels: a user-global file and a project-local file. Both are optional.

The global config lives at ~/.config/swival/config.toml (or $XDG_CONFIG_HOME/swival/config.toml if you set that variable). The project config is swival.toml in the base directory.

When both files exist, project settings override global settings. CLI flags override everything. The full precedence order is:

CLI flags > project config > global config > hardcoded defaults

To generate a starter config with all settings commented out, run one of:

swival --init-config            # global config
swival --init-config --project  # project config in current directory

Settings use the same names as CLI flags. Lists use TOML arrays instead of comma-separated strings.

provider = "openrouter"
model = "qwen/qwen3-235b-a22b"
max_turns = 250
allowed_commands = ["ls", "git", "python3"]
allowed_dirs = ["/opt/zig/lib/std"]
allowed_dirs_ro = ["/reference/docs", "~/datasets"]
quiet = false

Relative paths in allowed_dirs, allowed_dirs_ro, skills_dir, and reviewer resolve against the config file's parent directory, not the working directory. Tilde paths like ~/projects expand to the home directory.

If a project config contains api_key inside a git repository, Swival prints a warning because the key could be committed accidentally. Prefer environment variables for credentials.

The --system-prompt and no_system_prompt settings are mutually exclusive in config files, just as they are on the command line.

The library API (Session class) does not auto-load config files. If you want config file support in library code, call load_config() and config_to_session_kwargs() explicitly.

Project Instruction Files

Swival can load two project-local instruction files from the base directory during startup. CLAUDE.md is injected as <project-instructions>...</project-instructions>, and AGENTS.md is injected as <agent-instructions>...</agent-instructions>. If both files exist, Swival loads both in that order.

Each file is capped at 10,000 characters. These instructions are appended to the built-in system prompt, which makes them a practical place to encode house rules such as test commands, coding conventions, and dependency policies.

This is a Go project using Chi for routing. Tests use testify.
Always run `go test ./...` after making changes.
Don't add dependencies without asking.

Use --no-instructions when you do not want Swival to read either file.

swival --no-instructions "task"

If you set --system-prompt, project instruction files are also skipped because you are providing the full prompt text directly.

System Prompt Control

The built-in prompt is stored in swival/system_prompt.txt and defines default behavior, tool policy, and coding expectations.

You can replace it completely with --system-prompt.

swival --system-prompt "You are a security auditor. Only report vulnerabilities." "Audit src/"

You can also remove the system message entirely with --no-system-prompt.

swival --no-system-prompt "Just answer: what is 2+2?"

--system-prompt and --no-system-prompt are mutually exclusive.

When a system message is present, Swival appends the current local date and time to that system content.

Sampling And Reproducibility

--temperature and --top-p control response sampling.

swival --temperature 0.3 --top-p 0.9 "task"

If you do not set --temperature, provider defaults apply. --top-p defaults to 1.0.

--seed passes a deterministic seed when the provider supports it.

swival --seed 42 "task"

Seeded runs are usually more stable, but identical output is still not guaranteed across all providers, model versions, and hardware environments.

Turn And Token Limits

--max-turns limits how many agent-loop iterations are allowed.

swival --max-turns 10 "quick task"

The default turn limit is 100. If the loop reaches this limit without a final answer, Swival exits with code 2.

--max-output-tokens limits tokens generated per model call.

swival --max-output-tokens 16384 "task"

The default is 32768. If prompt size and context constraints require it, Swival clamps output budget downward automatically.

--max-context-tokens sets requested context length.

swival --max-context-tokens 65536 "task"

For LM Studio, this can trigger a model reload. When both --max-context-tokens and --max-output-tokens are set, --max-output-tokens must be less than or equal to context length.