fix(invariants): assert runtime relationships, not API shapes

packages/core/system-prompt/src/invariant.ts

@@ -1,31 +1,50 @@
-/** Package-owned runtime contract checks for `@deepseek-ai/dsh-system-prompt`. @module @deepseek-ai/dsh-system-prompt/invariant */
+/** Package-owned prompt-assembly invariants. @module @deepseek-ai/dsh-system-prompt/invariant */
 
 import type { Context } from 'cordis'
-import { observePluginInvariant, type InvariantInstaller } from '@deepseek-ai/dsh-invariants'
+import type { InvariantFailure, InvariantInstaller } from '@deepseek-ai/dsh-invariants'
+import type { PromptAssembly } from './index.ts'
 
 const PACKAGE_NAME = '@deepseek-ai/dsh-system-prompt'
+const VARIABLE_NAME = /^[a-z][a-z0-9_]*$/
 
 /** Cordis companion plugin name. */
 export const name = 'system-prompt-invariant'
-/** Services required before the companion can register. */
+/** Service required before the companion can reserve package ownership. */
 export const inject = ['invariants']
 
-/** Install checks for this package's active plugin fibers. */
+/** Validate the authoritative assembly returned by the waterfall. */
+function validateAssembly(assembly: PromptAssembly, fail: InvariantFailure): void {
+  const sectionNames = new Set<string>()
+  for (const section of assembly.sections) {
+    if (section.name.length === 0) fail('assembled section names must be non-empty')
+    if (sectionNames.has(section.name)) fail(`assembled section name ${JSON.stringify(section.name)} is duplicated`)
+    sectionNames.add(section.name)
+    if (typeof section.text !== 'string') fail(`assembled section ${JSON.stringify(section.name)} text must be a string`)
+  }
+
+  for (const tool of assembly.tools) {
+    if (tool.name.length === 0) fail('assembled tool names must be non-empty')
+  }
+
+  for (const [name, value] of Object.entries(assembly.variables)) {
+    if (!VARIABLE_NAME.test(name)) fail(`assembled variable name ${JSON.stringify(name)} is invalid`)
+    if (value !== undefined && typeof value !== 'string') {
+      fail(`assembled variable ${JSON.stringify(name)} must be a string or undefined`)
+    }
+  }
+}
+
+/** Install validation around the authoritative assembly waterfall result. */
 const install: InvariantInstaller = (ctx, fail) => {
-  observePluginInvariant(ctx, fail, {
-    name: 'SystemPrompt',
-    effects: [
-      'ctx.provide("systemPrompt")',
-      'systemPrompt.section()',
-    ],
-    services: [
-      'systemPrompt',
-    ],
-  })
+  ctx.on('system-prompt/assemble', async (_assembly, _context, next) => {
+    const assembled = await next()
+    validateAssembly(assembled, fail)
+    return assembled
+  }, { global: true, prepend: true })
 }
 
 /**
- * Register this package's invariant companion.
+ * Register the system-prompt invariant companion.
  * @param ctx - Cordis context carrying the invariant service.
  * @returns the installed registration's disposer after setup succeeds.
  */

packages/core/system-prompt/tests/invariant.spec.ts

@@ -0,0 +1,44 @@
+import { describe, expect, it } from 'vitest'
+import { Context } from 'cordis'
+import type { PromptAssembly } from '@deepseek-ai/dsh-system-prompt'
+import * as SystemPromptInvariant from '@deepseek-ai/dsh-system-prompt/invariant'
+import InvariantService from '@deepseek-ai/dsh-invariants'
+
+async function setup(): Promise<Context> {
+  const ctx = new Context()
+  await ctx.plugin(InvariantService)
+  await ctx.plugin(SystemPromptInvariant)
+  return ctx
+}
+
+const valid = (): PromptAssembly => ({
+  sections: [{ name: 'identity', text: 'prompt' }],
+  tools: [{ name: 'echo', description: 'Echo', parameters: {} }],
+  variables: { cwd: '/repo', optional: undefined },
+})
+
+async function assemble(ctx: Context, result: PromptAssembly): Promise<PromptAssembly> {
+  return ctx.waterfall(
+    ctx as never, 'system-prompt/assemble', valid(), {},
+    () => Promise.resolve(result),
+  )
+}
+
+describe('system-prompt invariants', () => {
+  it('accepts a well-formed authoritative assembly', async () => {
+    const ctx = await setup()
+    await expect(assemble(ctx, valid())).resolves.toEqual(valid())
+  })
+
+  it.each([
+    [{ ...valid(), sections: [{ name: '', text: 'x' }] }, /section names must be non-empty/],
+    [{ ...valid(), sections: [{ name: 'x', text: 'a' }, { name: 'x', text: 'b' }] }, /section name "x" is duplicated/],
+    [{ ...valid(), sections: [{ name: 'x', text: 1 as never }] }, /section "x" text must be a string/],
+    [{ ...valid(), tools: [{ name: '', description: 'x', parameters: {} }] }, /tool names must be non-empty/],
+    [{ ...valid(), variables: { Bad: 'x' } }, /variable name "Bad" is invalid/],
+    [{ ...valid(), variables: { value: 1 as never } }, /variable "value" must be a string or undefined/],
+  ])('rejects malformed authoritative assembly %#', async (assembly, message) => {
+    const ctx = await setup()
+    await expect(assemble(ctx, assembly)).rejects.toThrow(message)
+  })
+})