Sarvam Coder Extension (Minimal v1)

This is a VS Code extension (no local web server), designed to send user coding tasks and request model to provide a response for the following tools implemented within the extension:

• Read File(s) [read_file]
• Search File(s) [search_files]
• List file(s) [list_files]
• List Code definition Name(s) [list_code_definition_names]
• Search/Replace [apply_diff, search_and_replace]
• Write File [write_to_file]
• Insert Content [insert_content]
• Execute Command [execute_command]
• Followup Question [ask_followup_question]
• To Do List [update_todo_list]
• Attempt Completion [attempt_completion]

Tool structure

Tool parsing and execution are split into small modules:

• Parser: lib/tools/parser.js extracts tool calls + args.
• Helpers: lib/tools/helpers.js for path safety and diff parsing.
• Runner entrypoint: lib/tools/run-tool.js routes to a single tool handler.
• Tool handlers: lib/tools
  • read_file -> lib/tools/read-file.js
  • list_files -> lib/tools/list-files.js
  • search_files -> lib/tools/search-files.js
  • write_to_file -> lib/tools/write-to-file.js
  • apply_diff -> lib/tools/apply-diff.js
  • search_and_replace -> lib/tools/search-and-replace.js
  • insert_content -> lib/tools/insert-content.js
  • list_code_definition_names -> lib/tools/list-code-definition-names.js
  • update_todo_list -> lib/tools/update-todo-list.js

Tool build + flow

1. The system prompt is assembled from prompts/coder.txt and runtime context.
2. Raw request/response payloads are logged per task; system prompt content is hidden in the log UI.
3. The assistant output is parsed for a tool call, then routed through lib/tools/index.js.
4. Only read/write/execute pause for approval; other tools auto-approve.
5. Tool results are persisted in history as raw text but displayed in readable form; thinking blocks are expandable.

Launch in a new VS Code window

npm install
npm run verify

npm run verify launches an Extension Development Host window using this extension.

Where to find the UI

In the new window:

• Open the Activity Bar item Sarvam.
• Open the Sarvam Coder view.

The view includes:

• Left assistant chat area and input
• Settings fields: Base URL, API Key, Model, Context Window Size
• History with search
• Auto-approve showing only Read/Write/Execute

Policy behavior in extension host

• Fixed system prompt is applied for each request. Available in prompts/coder.txt.
• Runtime context is collected each request:
  • OS and shell
  • Workspace root
  • Project metadata and relevant structure
• Query-driven search runs for find/locate/search/inspect requests.
• Before any write attempt, a checkpoint is created automatically.
• Writes use patch-style targeted edits.
• History tracks write attempts with checkpoint IDs.

Checkpoint location

.sarvam/checkpoints/<timestamp>-<request-id>.json

Checkpoint content:

• Timestamp
• Request ID
• Target file list
• Pre-change snapshot
• Planned patch diff