Tianyi Cui
6143537d4e
# Conflicts: # docs/cordis-catalog/events.md # docs/cordis-catalog/services.md # docs/core-data-structures/bash.md # docs/core-data-structures/core.md # docs/event-producer-consumer.md # docs/module-graph.md # packages/bash/bash/src/types.ts # packages/bash/tool-bash/README.md # packages/bash/tool-bash/src/index.ts # packages/bash/tool-bash/tests/tools.spec.ts # packages/examples/agent-spine-demo/README.md # packages/examples/agent-spine-demo/tests/agent-core.spec.ts # packages/subagent/tool-subagent/tests/tool-subagent.spec.ts # packages/util/brand/README.md # packages/util/brand/src/index.ts
dsh-brand
The Branded<B> nominal-typing primitive — a tiny, type-only package (no runtime code, no harness-package dependency) shared by every package that owns a cross-boundary id.
What Branded is
A brand makes structurally-identical strings non-interchangeable at the type level: a SessionId cannot be passed where a CallId is expected, even though both are plain strings at runtime.
import type { Branded } from '@deepseek-ai/dsh-brand'
export type SessionId = Branded<'SessionId'>
/** Brand a string as a SessionId (a plain cast — zero runtime cost). */
export function SessionId(id: string): SessionId {
return id as SessionId
}
Construction goes through the per-id factory in the owning package. Comparison, logging, JSON serialization, and the wire format behave as for an ordinary string; the brand is erased at compile time.
Policy: brand ids that cross package boundaries
A package brands the ids it owns — CallId in dsh-llm, the shared agent/session SessionId in dsh-session, and TaskId in dsh-tasks. Brand cross-package ids that could plausibly be confused; not every string needs one.
This package owns only the primitive. Keeping it dependency-free lets dsh-tasks, for example, brand TaskId without importing an unrelated capability package merely to reach Branded.