@humanlayer/agentlayer-filesystem

Filesystem-backed implementations of agentlayer-core's tool interfaces (read, write, edit, apply_patch, glob, grep, list, bash), plus the hooks and prompts needed to assemble a real coding agent that operates on a local directory. Where agentlayer-core defines what a tool is (schema + description via ReadTool, EditTool, etc.), this package provides the executors that actually touch disk and spawn processes.

Install

bun add @humanlayer/agentlayer-filesystem

Usage

Build a full Claude- or Codex-style toolset for a working directory in one call:

import { createClaudeCodingAgentToolset, createAgentFilesystemHooks, createAgentSystemPrompt } from '@humanlayer/agentlayer-filesystem'

const tools = await createClaudeCodingAgentToolset({ cwd: '/repo' })
// { bash, read, write, edit, glob, grep, list, skill, web_fetch, ... }

const hooks = createAgentFilesystemHooks({ cwd: '/repo' })
// { preToolUse, postToolUse, preRequest } — wasted-read prevention,
// read-before-write enforcement, output truncation, file-state tracking

const system = await createAgentSystemPrompt({ cwd: '/repo', model: 'claude-sonnet-4-5' })

createCodexCodingAgentToolset builds the Codex-flavored equivalent (apply_patch instead of write/edit). Both are composed from createClaudeAgentFilesystemToolset / createCodexAgentFilesystemToolset (filesystem tools only) plus createCodingAgentAuxToolset (skill, agent/subagents, web_fetch, web_search).

Individual tool factories are also exported for manual composition, e.g. createReadTool({ cwd }), createBashTool({ cwd }), createGrepTool({ cwd }) — each returns a Tool built via <Interface>.define(executor, { description }) from @humanlayer/agentlayer-core/interfaces.

Subpath exports

• . — everything below
• ./tools — tool factories (createReadTool, createWriteTool, createEditTool, createApplyPatchTool, createGlobTool, createGrepTool, createListTool, createMultiEditTool, createReadMultimodalTool, createBashTool, createSkillToolFromDirs/createSkillToolFromRepoDirs, createWebSearchTool)
• ./hooks — createAgentFilesystemHooks and the pieces it's built from
• ./prompts — createAgentSystemPrompt, environmentPrompt, repoInstructionsPrompt
• ./coding-agent — the toolset/hooks composers shown above

Key pieces

• Tools (src/tools/): each wraps Node's fs/promises (or ripgrep/bash subprocesses) behind the matching core Tool interface. read/write/edit resolve paths via expandPath (~ and cwd-relative resolution). grep shells out to ripgrep, falling back to a JS-regex file walk (fsGrepFallback) if rg is unavailable. glob/grep cap results at 100 matches, most-recently-modified first.
• Hooks (src/hooks/): createAgentFilesystemHooks({ cwd, outputTruncation? }) wires together:
  • createWastedReadHook / createReadBeforeWriteHook (pre-tool-use) — block re-reading unchanged file ranges and require a fresh read before write/edit/apply_patch, tracked via SHA-256 hashes in agent state.
  • createFileStateTrackingHook (post-tool-use) — records read/verification state after read/write/edit/apply_patch.
  • create{Bash,Glob,Grep,List}OutputTruncationHook — truncate large tool outputs and spill the full output to a temp file via saveFullOutput. createReadTruncationHook truncates large reads and hints to continue at a higher offset (no temp file).
• Prompts (src/prompts/): createAgentSystemPrompt assembles [persona, repoInstructions?, environment?, ...additions] for a given model. repoInstructionsPrompt searches CLAUDE.md/AGENTS.md/CONTEXT.md (cwd, then git root) or layers multiple instruction sources via instruction-resolver. environmentPrompt reports cwd/platform/git-repo status.

Toolset assembly

flowchart LR
    subgraph "agentlayer-filesystem"
        FS["createClaudeAgentFilesystemToolset\n(read/write/edit/glob/grep/list/bash)"]
        AUX["createCodingAgentAuxToolset\n(skill/agent/web_fetch/web_search)"]
        HOOKS["createAgentFilesystemHooks"]
    end
    CORE["agentlayer-core\nTool interfaces + defineTool"] --> FS
    FS --> TOOLSET["createClaudeCodingAgentToolset"]
    AUX --> TOOLSET
    HOOKS --> AGENT["agent loop"]
    TOOLSET --> AGENT

Depends on

@humanlayer/agentlayer-core (tool interfaces, prompts, hooks primitives, utils) and the ripgrep npm package for grep.