Freeze the Agent Tool Catalog at Cost Class Zero

Description and use

Create a static tools.freeze.toml, commit it, and load it before app initialization, validating each tool against cost class and limits. Any new tool outside the file causes the build to fail.

Problem

A solo founder needs to ship an agent‑backed indie API the same day while guaranteeing that no paid or vendor‑managed tools are invoked, but still allowing local or free‑net tools.

Outcome

The workflow ensures that only pre‑approved, zero‑cost tools are callable, preventing accidental billing and enabling same‑day indie API launches.

Workflow

• 1. Create a tools.freeze.toml file listing all allowed tools with cost_class, max_calls, max_ms, and allow_url if needed.
• 2. Commit the freeze file to source control and do not generate it in CI.
• 3. Load the freeze in a module that imports no vendor SDKs before the app object is created.
• 4. Parse the TOML, validate uniqueness of names, enforce cost_class rules, and check allow_url for free_net tools.
• 5. Reject the build if the freeze is missing, duplicated names exist, or a tool violates its cost_class constraints.
• 6. During runtime, dispatch every tool call through a dry‑run ledger that enforces max_calls and max_ms per request.
• 7. Reject any call that would exceed the defined budgets or invoke a forbidden tool.

Evidence

The catalog must load in a module that imports no vendor SDK. Parse TOML, then refuse to boot if the file is missing, if two tools share a name, or if any free_net row lacks an exact allow_url.

Source

Tool calling is how an AI‑drafted handler reaches the rest of the world. A model that can register charge_card, embed_via_vendor, or publish_to_managed_queue will do so with confident names and tidy type hints.

Source