Example: Code Agent

Document ID: EX-003
File Path: docs/16-examples/code-agent.md
Version: 1.0.0
Status: Draft
Owner: Developer Relations Team
Last Updated: 2026-06-27

1. Goal

Build a tool-using agent that operates on a repository — reading files, running commands, and proposing changes — with tools executed safely in the Tool Runtime sandbox.

2. Tools Used

Tool	Purpose	Permissions
`fs.read` / `fs.write`	Read/edit files	`fs:read`/`fs:write:/workspace`
`shell.run`	Run build/test	sandboxed, no egress
`git.diff` / `git.commit`	Version control	`fs:*:/workspace`

These run sandboxed with default-deny egress (tool isolation); the agent gets only the declared grants.

3. Define the Agent

agents/code-agent.yaml:

kind: Agent
metadata: { name: code-agent }
spec:
  model_selector: { capability: chat, class: frontier }
  instructions: |
    You are a coding assistant. Read relevant files before editing.
    Run tests after changes. Propose a git diff; do not commit without approval.
  tools: [fs.read, fs.write, shell.run, git.diff]
  policies: [no-network-egress]
  budget: { max_cost_usd: 1.00 }

A frontier-class model is selected for harder reasoning; a policy forbids egress.

4. Run

wovyr agents run -f agents/code-agent.yaml --stream \
  --input '{"message":"Add input validation to parse_config and run the tests."}'

The stream shows tool calls interleaved with reasoning:

tool_call · fs.read("src/config.rs")
delta     · "I'll add validation for empty keys..."
tool_call · fs.write("src/config.rs", ...)
tool_call · shell.run("cargo test")  → exit 0
tool_call · git.diff                 → proposed patch
done      · tokens: 9.2k, cost_usd: 0.21, tool_calls: 4

5. Sandbox & Safety

Each tool runs in an ephemeral sandbox; shell.run has no network and a CPU/mem/time limit.
git.commit is not granted — the agent proposes a diff for human review, enforcing change control.
All tool executions are audited.

6. Add Human Approval (optional)

Wrap the commit step in a workflow with a human task so a reviewer approves the diff before git.commit runs — see Customer Support for the pattern.

7. Observe

Per-tool duration, resources, and cost in the trace inspector.
Tool execution metrics in monitoring.

9. Revision History

Version	Date	Description
1.0.0	2026-06-27	Initial Code Agent example