> ## Documentation Index
> Fetch the complete documentation index at: https://smithers.sh/llms.txt
> Use this file to discover all available pages before exploring further.

# <GatherAndSynthesize>

> Parallel gather from multiple sources, then synthesize into a unified result.

```ts theme={"theme":{"light":"github-light","dark":"github-dark"}}
// Props
import { GatherAndSynthesize } from "smithers-orchestrator";

type SourceDef = {
  agent: AgentLike;
  prompt?: string;        // optional; defaults to a generated gather prompt
  output?: OutputTarget;
  children?: ReactNode;        // overrides prompt
};

type GatherAndSynthesizeProps = {
  id?: string;                                       // default: "gather-and-synthesize"
  sources: Record<string, SourceDef>;
  synthesizer: AgentLike;
  gatherOutput: OutputTarget;
  synthesisOutput: OutputTarget;
  gatheredResults?: Record<string, unknown> | null;  // typically from ctx.outputMaybe()
  maxConcurrency?: number;                           // default: Infinity
  synthesisPrompt?: string;
  skipIf?: boolean;
  children?: ReactNode;                              // overrides synthesisPrompt
};
```

```tsx theme={"theme":{"light":"github-light","dark":"github-dark"}}
<Workflow name="research">
  <GatherAndSynthesize
    sources={{
      docs: { agent: docsAgent, prompt: "Search the documentation." },
      code: { agent: codeAgent, prompt: "Analyze the codebase." },
      issues: { agent: issueAgent, prompt: "Review open issues." },
    }}
    synthesizer={synthesisAgent}
    gatherOutput={outputs.gathered}
    synthesisOutput={outputs.synthesis}
    gatheredResults={gathered}
  />
</Workflow>
```

## Notes

* Synthesis task auto-receives `needs` for every source, gating it on all gathers.
* Source `children` takes priority over `prompt`.
* When `gatheredResults` is provided, it is folded into the default synthesis prompt.

## Source

The `<GatherAndSynthesize>` implementation and the files it imports, straight from the package source. This section is generated; edit the source, not this block.

<CodeGroup>
  ```js GatherAndSynthesize.js theme={"theme":{"light":"github-light","dark":"github-dark"}}
  // @smithers-type-exports-begin
  /** @typedef {import("./GatherAndSynthesizeProps.ts").GatherAndSynthesizeProps} GatherAndSynthesizeProps */
  /** @typedef {import("./SourceDef.ts").SourceDef} SourceDef */
  // @smithers-type-exports-end

  import React from "react";
  import { Sequence } from "./Sequence.js";
  import { Parallel } from "./Parallel.js";
  import { Task } from "./Task.js";
  /**
   * <GatherAndSynthesize> — Parallel data collection from different sources,
   * then synthesis into a unified result.
   *
   * Composes Sequence, Parallel, and Task. First a Parallel block gathers data
   * from each source agent, then a synthesis Task receives all gathered data
   * and produces a combined output.
   * @param {GatherAndSynthesizeProps} props
   */
  export function GatherAndSynthesize(props) {
      if (props.skipIf)
          return null;
      const { id, sources, synthesizer, gatherOutput, synthesisOutput, gatheredResults, maxConcurrency, synthesisPrompt, children, } = props;
      const prefix = id ?? "gather-and-synthesize";
      const sourceNames = Object.keys(sources);
      // Step 1: Parallel gather from all sources
      const gatherTasks = sourceNames.map((name) => {
          const source = sources[name];
          const output = source.output ?? gatherOutput;
          const taskId = `${prefix}-gather-${name}`;
          const content = source.children ??
              source.prompt ??
              `Gather data from source "${name}".`;
          return React.createElement(Task, {
              key: taskId,
              id: taskId,
              output,
              agent: source.agent,
              label: `Gather: ${name}`,
              children: content,
          });
      });
      const gatherParallel = React.createElement(Parallel, {
          key: `${prefix}-gather`,
          id: `${prefix}-gather`,
          maxConcurrency,
      }, ...gatherTasks);
      // Step 2: Build needs + deps maps — the synthesis task depends on all gather
      // tasks (`needs` gates it until they are terminal) and resolves each gather's
      // output into its prompt (`deps`; `needs` alone is cache-context only and
      // injects nothing). `depsOptional` lets a failed gather be omitted rather
      // than deferring the synthesis forever.
      const needs = {};
      const deps = {};
      for (const name of sourceNames) {
          needs[name] = `${prefix}-gather-${name}`;
          deps[name] = sources[name].output ?? gatherOutput;
      }
      // Build synthesis prompt from gathered results
      const explicitPrompt = children ?? synthesisPrompt ??
          (gatheredResults
              ? `Synthesize the following gathered data into a unified result:\n\n${Object.entries(gatheredResults)
                  .map(([name, data]) => `## ${name}\n${JSON.stringify(data, null, 2)}`)
                  .join("\n\n")}`
              : undefined);
      const synthesisContent = explicitPrompt ??
          ((resolved) => {
              const gatheredText = sourceNames
                  .map((name) => `## ${name}\n${name in resolved ? JSON.stringify(resolved[name]) : "(no data — this source failed)"}`)
                  .join("\n\n");
              return `Synthesize the gathered data from sources: ${sourceNames.join(", ")}.\n\n${gatheredText}`;
          });
      const synthesisTask = React.createElement(Task, {
          key: `${prefix}-synthesize`,
          id: `${prefix}-synthesize`,
          output: synthesisOutput,
          agent: synthesizer,
          needs,
          deps,
          depsOptional: true,
          label: "Synthesize",
          children: synthesisContent,
      });
      return React.createElement(Sequence, null, gatherParallel, synthesisTask);
  }
  ```

  ```js Sequence.js theme={"theme":{"light":"github-light","dark":"github-dark"}}
  import React from "react";
  /** @typedef {import("./SequenceProps.ts").SequenceProps} SequenceProps */

  /**
   * @param {SequenceProps} props
   */
  export function Sequence(props) {
      if (props.skipIf)
          return null;
      // Sequence carries only a display label; pass a sanitized bag (align with
      // the sanitizing structural components) so control props don't leak through.
      // `label` names the phase group in run views (graph, the Claude /workflows
      // mirror) and is preserved in the persisted frame XML.
      const next = props.label === undefined ? {} : { label: props.label };
      return React.createElement("smithers:sequence", next, props.children);
  }
  ```

  ```js Parallel.js theme={"theme":{"light":"github-light","dark":"github-dark"}}
  import React from "react";
  /** @typedef {import("./ParallelProps.ts").ParallelProps} ParallelProps */

  /**
   * @param {ParallelProps} props
   */
  export function Parallel(props) {
      if (props.skipIf)
          return null;
      // Align prop sanitization with other structural components. `label` names
      // the phase group in run views (graph, the Claude /workflows mirror).
      const next = {
          maxConcurrency: props.maxConcurrency,
          subtreeConcurrency: props.subtreeConcurrency,
          id: props.id,
          ...(props.label === undefined ? {} : { label: props.label }),
      };
      return React.createElement("smithers:parallel", next, props.children);
  }
  ```

  ```js Task.js theme={"theme":{"light":"github-light","dark":"github-dark"}}
  // @smithers-type-exports-begin
  /**
   * @template D
   * @typedef {import("./InferDeps.ts").InferDeps<D>} InferDeps
   */
  /** @typedef {import("./OutputTarget.ts").OutputTarget} OutputTarget */
  // @smithers-type-exports-end

  import React from "react";
  import { renderToStaticMarkup } from "react-dom/server";
  import { markdownComponents } from "../markdownComponents.js";
  import { zodSchemaToJsonExample } from "../zod-to-example.js";
  import { SmithersError } from "@smithers-orchestrator/errors/SmithersError";
  import { SmithersContext } from "@smithers-orchestrator/react-reconciler/context";
  import { AspectContext } from "../aspects/AspectContext.js";
  import { AntigravityAgent } from "@smithers-orchestrator/agents/AntigravityAgent";
  import { ClaudeCodeAgent } from "@smithers-orchestrator/agents/ClaudeCodeAgent";
  import { GeminiAgent } from "@smithers-orchestrator/agents/GeminiAgent";
  import { PiAgent } from "@smithers-orchestrator/agents/PiAgent";
  /** @typedef {import("@smithers-orchestrator/agents/AgentLike").AgentLike} AgentLike */
  /** @typedef {import("./DepsSpec.ts").DepsSpec} DepsSpec */
  /**
   * @template Row, Output, D
   * @typedef {import("./TaskProps.ts").TaskProps<Row, Output, D>} TaskProps
   */

  /**
   * Reverse the HTML-entity escaping that renderToStaticMarkup applies to text
   * (& < > " '). Without this, a prompt like `a < b && c` reaches the agent as
   * `a &lt; b &amp;&amp; c`, and injected JSON schema hints (`"key"`) arrive as
   * `&quot;key&quot;`, both of which corrupt the agent-facing text.
   * `&amp;` is decoded last so an escaped literal (`&amp;lt;`, meaning the source
   * text `&lt;`) is not double-decoded into `<`.
   * @param {string} html
   * @returns {string}
   */
  function decodeHtmlEntities(html) {
      return html
          .replace(/&lt;/g, "<")
          .replace(/&gt;/g, ">")
          .replace(/&quot;/g, '"')
          .replace(/&#x27;/g, "'")
          .replace(/&#39;/g, "'")
          .replace(/&amp;/g, "&");
  }
  /**
   * Render a prompt React node to plain markdown text.
   *
   * If the prompt is a React element (e.g. a compiled MDX component), we inject
   * `markdownComponents` via the standard MDX `components` prop so that
   * renderToStaticMarkup outputs clean markdown instead of HTML. The static
   * render entity-escapes all text, so we decode the entities back to literal
   * characters before handing the prompt to the agent.
   * @param {unknown} prompt
   * @returns {string}
   */
  export function renderPromptToText(prompt) {
      if (prompt == null)
          return "";
      if (typeof prompt === "string")
          return prompt;
      if (typeof prompt === "number")
          return String(prompt);
      try {
          let element;
          if (React.isValidElement(prompt)) {
              // Inject markdown components into the element so MDX components
              // render fragments instead of HTML tags.
              element = React.cloneElement(prompt, {
                  components: markdownComponents,
              });
          }
          else {
              element = React.createElement(React.Fragment, null, prompt);
          }
          return decodeHtmlEntities(renderToStaticMarkup(element))
              .replace(/\n{3,}/g, "\n\n")
              .trim();
      }
      catch (err) {
          const result = String(prompt ?? "");
          if (result === "[object Object]") {
              throw new SmithersError("MDX_PRELOAD_INACTIVE", `MDX prompt could not be rendered — the prompt resolved to [object Object] instead of a React component.\n\n` +
                  `This usually means the MDX preload is not active. Common causes:\n` +
                  `  • bunfig.toml uses [run] preload instead of top-level preload (the [run] section doesn't apply to dynamic imports)\n` +
                  `  • bunfig.toml is not in the current working directory\n` +
                  `  • mdxPlugin() is not registered in the preload script\n` +
                  `  • The MDX file is imported without a default import (use: import MyPrompt from "./prompt.mdx")\n\n` +
                  `Original error: ${err instanceof Error ? err.message : String(err)}`);
          }
          return result;
      }
  }
  /**
   * @param {unknown} value
   * @returns {value is import("zod").ZodObject<import("zod").ZodRawShape>}
   */
  function isZodObject(value) {
      return Boolean(value && typeof value === "object" && "shape" in value);
  }
  /**
   * @param {DepsSpec | undefined} deps
   * @param {Record<string, string> | undefined} needs
   * @returns {string[] | undefined}
   */
  function deriveDepNodeIds(deps, needs) {
      if (!deps)
          return undefined;
      const ids = new Set();
      for (const key of Object.keys(deps)) {
          const nodeId = needs?.[key] ?? key;
          if (nodeId)
              ids.add(nodeId);
      }
      return ids.size > 0 ? [...ids] : undefined;
  }
  /**
   * @param {string[] | undefined} dependsOn
   * @param {string[] | undefined} depNodeIds
   * @returns {string[] | undefined}
   */
  function mergeDependsOn(dependsOn, depNodeIds) {
      const merged = new Set();
      for (const id of dependsOn ?? [])
          merged.add(id);
      for (const id of depNodeIds ?? [])
          merged.add(id);
      return merged.size > 0 ? [...merged] : undefined;
  }
  /**
   * @param {any} ctx
   * @param {DepsSpec | undefined} deps
   * @param {Record<string, string> | undefined} needs
   * @param {boolean | undefined} depsOptional
   * @returns {Record<string, unknown> | null}
   */
  function resolveDeps(ctx, deps, needs, depsOptional) {
      if (!deps)
          return Object.create(null);
      const keys = Object.keys(deps);
      if (keys.length === 0)
          return Object.create(null);
      const resolved = Object.create(null);
      for (const key of keys) {
          const target = deps[key];
          const nodeId = needs?.[key] ?? key;
          const value = ctx.outputMaybe(target, { nodeId });
          if (value === undefined) {
              // Optional deps mode: omit unresolved keys instead of deferring the
              // whole task. Used when the task is already gated by `needs`/`dependsOn`
              // and upstream tasks may legitimately fail (continueOnFail) without
              // producing an output row.
              if (depsOptional)
                  continue;
              return null;
          }
          resolved[key] = value;
      }
      return resolved;
  }
  /**
   * @param {AgentLike} agent
   * @param {string[] | undefined} allowTools
   * @returns {AgentLike}
   */
  function applyCliToolAllowlist(agent, allowTools) {
      if (!allowTools) {
          return agent;
      }
      if (agent instanceof ClaudeCodeAgent) {
          const opts = { ...agent.opts };
          if (allowTools.length === 0) {
              return new ClaudeCodeAgent({
                  ...opts,
                  allowedTools: [],
                  tools: "",
              });
          }
          return new ClaudeCodeAgent({
              ...opts,
              allowedTools: [...allowTools],
          });
      }
      if (agent instanceof PiAgent) {
          const opts = { ...agent.opts };
          if (allowTools.length === 0) {
              return new PiAgent({
                  ...opts,
                  tools: [],
                  noTools: true,
              });
          }
          return new PiAgent({
              ...opts,
              tools: [...allowTools],
              noTools: false,
          });
      }
      if (agent instanceof GeminiAgent) {
          const opts = { ...agent.opts };
          return new GeminiAgent({
              ...opts,
              allowedTools: [...allowTools],
          });
      }
      if (agent instanceof AntigravityAgent) {
          const opts = { ...agent.opts };
          return new AntigravityAgent({
              ...opts,
              allowedTools: [...allowTools],
          });
      }
      return agent;
  }
  /**
   * @param {unknown} ctx
   * @param {string[] | undefined} allowTools
   * @returns {string[] | undefined}
   */
  function resolveCliToolAllowlist(ctx, allowTools) {
      if (allowTools !== undefined) {
          return allowTools;
      }
      const cliAgentToolsDefault = ctx && typeof ctx === "object"
          ? ctx.__smithersRuntime?.cliAgentToolsDefault
          : undefined;
      return cliAgentToolsDefault === "explicit-only" ? [] : undefined;
  }
  /**
   * @template Row, Output, D
   * @param {TaskProps<Row, Output, D>} props
   * @returns {React.ReactElement | null}
   */
  export function Task(props) {
      const { children, agent, fallbackAgent, deps, depsOptional, ...rest } = props;
      const taskContext = props.smithersContext ?? SmithersContext;
      const ctx = React.useContext(taskContext);
      const aspectCtx = React.useContext(AspectContext);
      const depNodeIds = deriveDepNodeIds(deps, rest.needs);
      if (deps && !ctx) {
          throw new SmithersError("CONTEXT_OUTSIDE_WORKFLOW", "Task deps require a workflow context. Build the workflow with createSmithers().");
      }
      const resolvedDeps = deps ? resolveDeps(ctx, deps, rest.needs, depsOptional) : undefined;
      if (deps && resolvedDeps == null) {
          // Deps not yet available — component defers until upstream tasks complete.
          // This is normal reactive behavior; the task will re-render once deps are
          // ready. Record the deferral so the engine can distinguish a transient wait
          // from a permanent one: a deferral that survives to quiescence means a
          // dependency that can never resolve (e.g. a deps key that maps to a node id
          // no task produces), which would otherwise be a silent skip.
          ctx?.recordDeferredDep?.(props.id, depNodeIds ?? []);
          return null;
      }
      // Build aspect metadata to attach to the task element so the engine can
      // enforce budgets and track metrics at execution time.
      const aspectMeta = aspectCtx ? buildAspectMeta(aspectCtx) : undefined;
      const agentChain = Array.isArray(agent)
          ? fallbackAgent
              ? [...agent, fallbackAgent]
              : agent
          : agent && fallbackAgent
              ? [agent, fallbackAgent]
              : agent;
      const effectiveAllowTools = resolveCliToolAllowlist(ctx, rest.allowTools);
      const restrictedAgentChain = Array.isArray(agentChain)
          ? agentChain.map((entry) => applyCliToolAllowlist(entry, effectiveAllowTools))
          : agentChain
              ? applyCliToolAllowlist(agentChain, effectiveAllowTools)
              : agentChain;
      const nextDependsOn = mergeDependsOn(rest.dependsOn, depNodeIds);
      const childValue = typeof children === "function" && (agent || deps)
          ? children(resolvedDeps ?? Object.create(null))
          : children;
      if (agent) {
          // Auto-inject `schema` prop into React element children when output is a ZodObject
          let childElement = childValue;
          const schemaForInjection = props.outputSchema ??
              (isZodObject(props.output) ? props.output : undefined);
          if (React.isValidElement(childValue) && schemaForInjection) {
              childElement = React.cloneElement(childValue, {
                  schema: zodSchemaToJsonExample(schemaForInjection),
              });
          }
          const prompt = renderPromptToText(childElement);
          return React.createElement("smithers:task", {
              ...rest,
              dependsOn: nextDependsOn,
              waitAsync: rest.async === true,
              agent: restrictedAgentChain,
              __smithersKind: "agent",
              ...aspectMeta,
          }, prompt);
      }
      if (typeof children === "function" && !deps) {
          const nextProps = {
              ...rest,
              dependsOn: nextDependsOn,
              waitAsync: rest.async === true,
              __smithersKind: "compute",
              __smithersComputeFn: children,
              ...aspectMeta,
          };
          return React.createElement("smithers:task", nextProps, null);
      }
      const nextProps = {
          ...rest,
          dependsOn: nextDependsOn,
          waitAsync: rest.async === true,
          __smithersKind: "static",
          __smithersPayload: childValue,
          __payload: childValue,
          ...aspectMeta,
      };
      return React.createElement("smithers:task", nextProps, null);
  }
  /**
   * Build the __aspects metadata object from the current AspectContext.
   * This is attached to the smithers:task element props so the engine can read
   * budgets and tracking config at execution time.
   * @param {{
   *     tokenBudget?: unknown;
   *     latencySlo?: unknown;
   *     tracking?: unknown;
   *     accumulator?: unknown;
   * }} aspectCtx
   * @returns {{ __aspects: Record<string, unknown> }}
   */
  function buildAspectMeta(aspectCtx) {
      return {
          __aspects: {
              tokenBudget: aspectCtx.tokenBudget,
              latencySlo: aspectCtx.latencySlo,
              tracking: aspectCtx.tracking,
              accumulator: aspectCtx.accumulator,
          },
      };
  }
  ```

  ```ts GatherAndSynthesizeProps.ts theme={"theme":{"light":"github-light","dark":"github-dark"}}
  import type React from "react";
  import type { AgentLike } from "@smithers-orchestrator/agents/AgentLike";
  import type { OutputTarget } from "./OutputTarget.ts";
  import type { SourceDef } from "./SourceDef.ts";

  export type GatherAndSynthesizeProps = {
  	id?: string;
  	/** Record mapping source names to source definitions. */
  	sources: Record<string, SourceDef>;
  	/** Agent that synthesizes gathered data. */
  	synthesizer: AgentLike;
  	/** Default output schema for each source gather task. */
  	gatherOutput: OutputTarget;
  	/** Output schema for the synthesis task. */
  	synthesisOutput: OutputTarget;
  	/** Gathered results keyed by source name. Typically from ctx.outputMaybe(). */
  	gatheredResults?: Record<string, unknown> | null;
  	/** Max parallel gatherers. */
  	maxConcurrency?: number;
  	/** Prompt for the synthesis task. If omitted, a default prompt is generated. */
  	synthesisPrompt?: string;
  	skipIf?: boolean;
  	children?: React.ReactNode;
  };
  ```

  ```ts SourceDef.ts theme={"theme":{"light":"github-light","dark":"github-dark"}}
  import type React from "react";
  import type { AgentLike } from "@smithers-orchestrator/agents/AgentLike";
  import type { OutputTarget } from "./OutputTarget.ts";

  export type SourceDef = {
  	agent: AgentLike;
  	/** Prompt for this source. A string or ReactNode. */
  	prompt?: string;
  	/** Output schema for this specific source. Overrides `gatherOutput`. */
  	output?: OutputTarget;
  	children?: React.ReactNode;
  };
  ```
</CodeGroup>