Templates

What Are Templates?

Templates are reusable sandbox configurations. Define the base image, guardrails, environment variables, and allowed domains once — then reference the template across runs.

There are two types:

System templates — global defaults provided by coSPEC. Read-only — cannot be modified or deleted.
Workspace templates — created by your team, fully editable

Base Images

Image	Pre-installed
`node-22`	Node.js 22, npm, git, common build tools
`python-3.12`	Python 3.12, pip, git, common build tools
`php-8.3`	PHP 8.3, Composer, common extensions (bcmath, gd, intl, mbstring, pdo, zip), git, common build tools

Sandbox Sizes

Every template has a size that controls how much CPU, memory, and disk the sandbox gets. Set it when creating or updating a template.

Size	CPU	RAM	Disk
`s` — Small	1 vCPU	2 GB	5 GB
`m` — Medium	2 vCPU	4 GB	10 GB
`l` — Large	4 vCPU	8 GB	20 GB

The default size is m. Choose a larger size when agents need to build large projects, run memory-heavy test suites, or work with big repositories.

If a sandbox exceeds its memory limit, the run fails with RUN_RESOURCE_LIMIT_EXCEEDED.

Default Guardrails

Templates set default guardrails for all runs that use them. Individual runs can override these values.

Guardrail	Default	Description
`maxTurns`	100	Maximum agent turns
`maxCostUsd`	$5	Maximum Anthropic API cost
`timeoutMinutes`	30	Maximum wall-clock time

Environment Variables

Set default environment variables on a template. When a run specifies its own env, the values are merged — run values win on conflict.

Network Access

All sandboxes start with a base set of allowed domains. Custom domains you add to a template are additive.

Default Allowed Domains

Category	Domains	Ports
Git providers	`github.com`, `.github.com`, `.githubusercontent.com`, `gitlab.com`, `.gitlab.com`, `bitbucket.org`, `.bitbucket.org`	443, 22
Anthropic	`api.anthropic.com`, `statsig.anthropic.com`, `claude.ai`	443
npm / Yarn	`registry.npmjs.org`, `*.npmjs.org`, `registry.yarnpkg.com`	443
PyPI	`pypi.org`, `files.pythonhosted.org`	443
Cloud storage	`storage.googleapis.com`	443
System packages	`.ubuntu.com`, `.debian.org`	80, 443

All other outbound traffic is blocked. Private IP ranges (10.x, 172.16.x, 192.168.x, link-local) are always blocked.

When using a self-hosted GitLab instance, the instance domain is automatically added to the sandbox's egress allowlist for the run.

Custom Allowed Domains

Add up to 20 additional domains per template. Wildcard support is available (e.g. *.example.com).

Blocked values: IP addresses, localhost, .local, .internal.

Terminal

curl -X POST https://api.cospec.io/v1/templates \
  -H "Authorization: Bearer csk_live_..." \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Backend Service",
    "slug": "backend-service",
    "baseImage": "node-22",
    "size": "m",
    "guardrails": {
      "maxTurns": 200,
      "maxCostUsd": 10,
      "timeoutMinutes": 45
    },
    "egressDomains": [
      "*.example.com",
      "api.stripe.com"
    ],
    "envVars": {
      "NODE_ENV": "development"
    }
  }'

On this page