---name: forge-idiomatic-developerdescription: Load this whenever you are about to write, edit, or review code that uses the forgelib library in any language.---

Building on Forge

Forge provides the backend primitives most applications need, with Postgres backends by default. Initialize one client from forge.toml and use Forge's actual API rather than inferring behavior from similar libraries.

Use the Forge version resolved by the project. Check its installed declarations when an exact signature or behavior matters; when editing Forge itself, use the repository source.

Read the relevant sections of the language reference:

• Node.js/TypeScript: references/node.md
• Python: references/python.md
• Rust: references/rust.md
• Go: references/go.md

Read these only when they apply:

• references/runtime-contract.md for configuration, errors, deployment, queues, scheduling, rate limits, pub/sub, presigning, flags, or maintenance.
• references/application-design.md for a nontrivial service, storage decision, authentication workflow, cross-system side effects, lifecycle, or test strategy. Do not preload unrelated language references.

Pick the primitive deliberately

Need	Forge primitive	Core constraint
Direct-key values, TTL state, counters, CAS	kv	Single-key operations; weakly consistent prefix scans
Durable background work and retry	queue	Requires an owning consumer; at-least-once
Ephemeral live fan-out	pubsub	At-most-once, live subscribers only
Files and presigned transfer URLs	blob	Application must enforce its ownership policy
Passwords, sessions, API keys, one-time tokens	auth	Application owns user and authorization records
Request throttling	ratelimit	Fail mode is a security/availability choice; not a business counter
Cron or delayed enqueue	schedule	Application must run scheduler ticks
Runtime settings and rollout flags	config	Cached; secrets remain environment-backed

Core contracts

• Queue delivery is concurrent and at-least-once. Settle with the delivery receipt or leased job, not its stable id. Ack only after the logical effect succeeds.
• Scope idempotency to the logical effect. A job id is a useful base for redelivery, but fan-out may require job-id:recipient-id, and duplicate jobs may require a stable domain operation id.
• Use managed workers where practical. Retain their promise/task/future, signal shutdown, and await completion.
• Run scheduler and maintenance loops when the selected features require them.
• Keep connection strings server-side and keep Forge's internal tables private.
• Presigning requires a non-empty secret without an empty fallback. Authorize access and verify the issued method, key, expiry, maximum bytes, and signature exactly.

Before finishing

• Verify method names, sync/async use, option order, defaults, and error behavior against the project's installed Forge version.
• Confirm the chosen primitive supports the required behavior.
• Confirm every produced queue has an identified consumer in the deployed system; test redelivery at the logical side-effect boundary.
• Verify lifecycle behavior in the application's real process topology.
• Test the Forge boundary and the failure modes that matter to the change.