deepseek-harness/packages/core/tools/src/code-mode.ts

/**
 * Code Mode `run_code` transport. Programs call the registry's agent-visible
 * tools through nested, sequential executions; each sub-dispatch is logged for
 * reconstruction, while only the outer curated result enters model history.
 * @module @deepseek-ai/dsh-tools/src/code-mode
 */

import { parse } from 'node:path'
import { CallId, HarnessError } from '@deepseek-ai/dsh-llm'
import type { ContentBlock } from '@deepseek-ai/dsh-llm'
import type { CodeBindingFunction, CodeRunResult, CodeRuntime } from '@deepseek-ai/dsh-code-runtime'
import { snapshotJsonValue } from '@deepseek-ai/dsh-session'
import type { JsonValue } from '@deepseek-ai/dsh-session'
import { defineTool } from './schema.ts'
import type { ToolDefinition, ToolRegistry } from './index.ts'

declare module '@deepseek-ai/dsh-session' {
  interface SessionEventMap {
    /**
     * One bridged sub-dispatch from a `run_code` program: the parent
     * `run_code` call id, the deterministic sub-call id
     * (`<parent>:code:<n>`), the tool `name` with its JSON-normalized
     * `arguments` — the exact value dispatched, normalized BEFORE dispatch,
     * so this append can never fail on payload shape — whether the sub-call
     * errored, and a bounded `resultSummary` of its model-facing text. Before
     * bounding, occurrences of a non-root session workspace path are
     * normalized to `.` so host-specific absolute path lengths cannot change
     * the summary.
     * Log-only: `deriveMessages()` ignores it, so sub-calls never re-enter
     * model context; persistence and UIs get every call. Appended inside the
     * parent `run_code`'s execution (the bridge drains its queue before
     * returning), so the turn-enclosure invariant holds by construction.
     */
    'tool/code-dispatch': { parentCallId: CallId; subCallId: CallId; name: string; arguments: unknown; isError: boolean; resultSummary: string }
  }
}

/** The model-facing name of the Code Mode tool. */
export const RUN_CODE_NAME = 'run_code'

/** The `tools:sdk` section order: inside the 100–199 tool-guidance band, after per-tool guidance sections. */
export const SDK_SECTION_ORDER = 150

/**
 * Thrown by `run_code` when the program run itself failed — a program
 * exception, a budget expiry, an abort, or substrate death. Extends
 * {@link HarnessError} (`code: 'CODE_RUN_FAILED'`); the registry's execution
 * pipeline converts it into a structured `isError` result whose text carries
 * the failure kind plus the captured logs, so the model can self-correct.
 */
export class CodeRunFailedError extends HarnessError {
  constructor(message: string) {
    super(message, 'CODE_RUN_FAILED')
    this.name = 'CodeRunFailedError'
  }
}

/**
 * Cap for a `tool/code-dispatch` event's `resultSummary`. A log-ergonomics
 * constant, not config: the full result already flows to the program; the
 * summary exists so log readers see what a sub-call returned at a glance.
 */
const SUMMARY_MAX_CHARS = 200

/** Join Native content for the bounded durable sub-dispatch summary; non-text blocks become diagnostic placeholders. */
function textOf(content: ContentBlock[]): string {
  return content
    .map((block) => {
      switch (block.type) {
        case 'text': return block.text
        // ContentBlockMap is merge-extensible — future block kinds land here
        // deliberately (no assertNever on merge-extensible unions).
        default: return `[${block.type} content]`
      }
    })
    .join('\n')
}

/** Normalize workspace paths, then bound a sub-call's model-facing text for its durable log summary. */
function summarize(text: string, cwd: string | undefined): string {
  const stableText = cwd === undefined || cwd === parse(cwd).root
    ? text
    : text.replaceAll(cwd, '.')
  return stableText.length > SUMMARY_MAX_CHARS ? `${stableText.slice(0, SUMMARY_MAX_CHARS)}…` : stableText
}

/**
 * Snapshot one binding call's argument as lossless JSON, then clone it into
 * independent dispatch/log values so a tool mutation cannot desynchronize the
 * durable event from what was called.
 */
function jsonNormalizeArgs(value: unknown): { dispatched: unknown; logged: unknown } {
  let snapshot: JsonValue | undefined
  try {
    snapshot = snapshotJsonValue(value) as JsonValue | undefined
  } catch (error: unknown) {
    throw new Error(`tool arguments must be lossless JSON: ${error instanceof Error ? error.message : String(error)}`)
  }
  if (snapshot === undefined) {
    throw new Error('tool arguments must be lossless JSON (call the tool with an arguments object, e.g. `{}`)')
  }
  return { dispatched: structuredClone(snapshot), logged: structuredClone(snapshot) }
}

/** Render one present program completion value for the model-facing result text. */
function renderValue(value: JsonValue): string {
  return typeof value === 'string' ? value : JSON.stringify(value, null, 2)
}

/** The run_code result's `meta` payload (JSON-serializable; `presentResult` narrows it back). */
interface RunCodeMeta {
  logs: CodeRunResult['logs']
}

/** Canonical value returned by the outer Code Mode transport. */
type RunCodeOutput = { logs: string[]; result?: JsonValue }

/** Soft-narrow a result `meta` back to {@link RunCodeMeta} (replay may carry older shapes; presentation must not throw). */
function asRunCodeMeta(meta: unknown): RunCodeMeta | undefined {
  if (typeof meta !== 'object' || meta === null) return undefined
  const m = meta as Record<string, unknown>
  if (!Array.isArray(m.logs) || !m.logs.every(log => typeof log === 'string')) return undefined
  return m as unknown as RunCodeMeta
}

/**
 * Build the `run_code` {@link ToolDefinition}: one required `code` parameter,
 * executed through the dispatch bridge described above. The
 * registry reserves it as presentation infrastructure under non-native modes,
 * outside the filterable global/scoped capability layers.
 * @param registry - the owning registry (sub-calls go through its `execute`,
 *   bindings cover its registered tools).
 * @param requireRuntime - resolves `ctx.codeRuntime` or throws the loud
 *   misconfiguration error (shared with the registry's assembly-time checks).
 * @returns the registry-ready definition.
 */
export function createRunCodeTool(registry: ToolRegistry, requireRuntime: () => CodeRuntime): ToolDefinition {
  return defineTool({
    name: RUN_CODE_NAME,
    description:
      'Execute a TypeScript program against the available tools. Write the BODY of an '
      + 'async function (erasable syntax only; top-level `await` and `return` work) and '
      + 'call tools as `await tools.name(args)` per the declarations in the system prompt. '
      + 'Only what you print or return comes back — curate it.',
    parameters: {
      code: { type: 'string', required: true, description: 'The program: the body of an async TypeScript function.' },
    },
    output: {
      schema: {
        type: 'object',
        additionalProperties: false,
        properties: {
          logs: { type: 'array', required: true, items: { type: 'string' } },
          result: { type: 'json' },
        },
      },
      render: (_args, value) => {
        const rendered = value.result === undefined ? '' : renderValue(value.result)
        const parts = [value.logs.join('\n'), rendered].filter(part => part.length > 0)
        return [{ type: 'text', text: parts.length > 0 ? parts.join('\n') : '(run_code completed with no output)' }]
      },
      presentationMeta: (_args, value) => ({ logs: value.logs }),
    },
    async execute(args, exec): Promise<RunCodeOutput> {
      const runtime = requireRuntime()

      // The run-scoped abort: follows the outer signal in, and fires when the
      // run settles for ANY reason, so an in-flight sub-dispatch is aborted
      // (its executor kills on this signal) instead of orphaned, and
      // queued-unstarted dispatches are abandoned.
      const runController = new AbortController()
      const onOuterAbort = (): void => { runController.abort(exec.signal?.reason) }
      if (exec.signal?.aborted) onOuterAbort()
      exec.signal?.addEventListener('abort', onOuterAbort, { once: true })

      let dispatches = 0
      // The per-run serialization queue: every binding call chains onto the tail, so even
      // `Promise.all` executes the underlying tool calls one at a time in submission order (the
      // tool contract carries no concurrency-safety metadata yet).
      let queue: Promise<void> = Promise.resolve()
      const enqueue = <T>(task: () => Promise<T>): Promise<T> => {
        const turn = queue.then(() => {
          if (runController.signal.aborted) {
            throw new Error(`run_code run is over (${String(runController.signal.reason)}); tool call abandoned`)
          }
          return task()
        })
        queue = turn.then(() => undefined, () => undefined)
        return turn
      }

      // Read through a call, not a bare property: the abort state genuinely
      // changes across awaits, and a direct `.aborted` re-check after one
      // would be narrowed away by control flow analysis.
      const runOver = (): boolean => runController.signal.aborted

      const binding = (name: string): CodeBindingFunction => async (rawArgs: unknown): Promise<JsonValue> => {
        if (runOver()) {
          throw new Error(`run_code run is over (${String(runController.signal.reason)}); ${name} not dispatched`)
        }
        const normalized = jsonNormalizeArgs(rawArgs)
        const outcome = await enqueue(async () => {
          const n = ++dispatches
          const subCallId = CallId(`${String(exec.callId)}:code:${n}`)
          const result = await registry.execute({
            callId: subCallId,
            name,
            arguments: normalized.dispatched,
            ...exec.agent ? { agent: exec.agent } : {},
            parent: exec.token,
            signal: runController.signal,
          })
          for (const context of result.additionalContexts ?? []) {
            exec.deferContext(context)
          }
          const text = textOf(result.content)
          exec.agent?.session.append('tool/code-dispatch', {
            parentCallId: exec.callId,
            subCallId,
            name,
            // The SIBLING parse of the dispatched value: byte-identical JSON,
            // but a separate object — a tool mutating its args cannot desync
            // this record from what it actually received.
            arguments: normalized.logged,
            isError: result.isError,
            resultSummary: summarize(text, exec.agent.session.header.cwd),
          })
          return result.isError
            ? { isError: true as const, message: result.error.message }
            : { isError: false as const, value: result.value }
        })
        // A budget expiry or outer cancel that lands while this call was in
        // flight already aborted the dispatch; stop the program now rather
        // than hand it a result from a run that is over.
        if (runOver()) {
          throw new Error(`run_code run is over (${String(runController.signal.reason)}); ${name} result discarded`)
        }
        // The worker turns a binding rejection into ToolCallError and adds
        // only the binding name. Native content and internal error metadata
        // stay outside the program-facing failure contract.
        if (outcome.isError) throw new Error(outcome.message)
        return outcome.value
      }

      // Null-prototype + defineProperty, mirroring the worker-side namespace
      // build: a registered tool named `__proto__` must become an ordinary
      // own key (a plain-object assignment would hit the prototype setter,
      // silently dropping the binding), and the runtime host resolves
      // binding names as own properties only.
      const functions: Record<string, CodeBindingFunction> = Object.create(null) as Record<string, CodeBindingFunction>
      // Enumerate the CALLING AGENT's visible set (scoped tools join,
      // restricted globals vanish) — the same view the SDK section declared,
      // so a program can bind exactly what its prompt promised; sub-dispatch
      // re-resolves per call through the same view (exec.agent threads down).
      for (const schema of registry.schemas(exec.agent)) {
        if (schema.name === RUN_CODE_NAME) continue
        Object.defineProperty(functions, schema.name, { enumerable: true, value: binding(schema.name) })
      }

      try {
        let result: CodeRunResult
        try {
          result = await runtime.run({
            program: args.code,
            bindings: [{ global: 'tools', functions }],
            signal: runController.signal,
          })
        } finally {
          // Abort sub-dispatches and drain the folded queue before closing the turn.
          // Binding failures remain observable through their individual promises.
          runController.abort('run_code settled')
          await queue
        }

        if (result.error) {
          const logsText = result.logs.length > 0 ? `\nCaptured output:\n${result.logs.join('\n')}` : ''
          throw new CodeRunFailedError(`code run failed (${result.error.kind}): ${result.error.message}${logsText}`)
        }
        return {
          logs: result.logs,
          ...result.value !== undefined ? { result: result.value } : {},
        }
      } finally {
        exec.signal?.removeEventListener('abort', onOuterAbort)
      }
    },
    // ACP execute cards use the program as their visible title.
    presentCall: args => ({
      card: 'generic',
      title: args.code,
      kind: 'execute',
      rawInput: args.code,
    }),
    // Title omitted on the result: an update replaces only the fields it
    // carries, so the pending card's program title persists through
    // completion; the captured output rides as body content.
    presentResult: (_args, result) => {
      const meta = asRunCodeMeta(result.meta)
      if (!meta) return undefined
      const output = meta.logs.join('\n')
      return {
        card: 'generic',
        ...output.length > 0 ? { content: [{ type: 'text' as const, text: output }] } : {},
      }
    },
  })
}