What is adk-agent-builder?

A guide to building Python agents with Google's Agent Development Kit, a framework for applications where language models use tools and follow workflows. It covers individual agents, function steps, branching, delegation, pauses for human input, and pytest tests.

Use it to create agents, connect tools, build graph-based workflows, route between steps, delegate tasks between agents, add human approval pauses, and test the resulting code.

It helps you choose the right documented building block instead of guessing API names or connections. This reduces runtime errors when combining agents, tools, and workflow steps.

adk-agent-builder — Skill for Claude Code and Codex by joao-aires

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent

npx skills add joao-aires/agent-skills-public --skill adk-agent-builder

Clone the repo

git clone --depth 1 https://github.com/joao-aires/agent-skills-public

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/joao-aires/agent-skills-public/adk-agent-builder/github.svg)](https://agentmods.dev/skills/joao-aires/agent-skills-public/adk-agent-builder)

Your own site

<a href="https://agentmods.dev/skills/joao-aires/agent-skills-public/adk-agent-builder"><img src="https://agentmods.dev/badge/skills/joao-aires/agent-skills-public/adk-agent-builder/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/joao-aires/agent-skills-public/adk-agent-builder"><img src="https://agentmods.dev/badge/skills/joao-aires/agent-skills-public/adk-agent-builder.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 177 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 884 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin 100% copy Near-identical to another mod in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00177	$0.00884
Opus 5.5	$0.00071	$0.00354
Sonnet 5.5	$0.00035	$0.00177
Haiku 4.5	$0.00018	$0.00088

Measured yesterday against content hash 5690ecc21fa4, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

adk-agent-builder scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

100% identical to adk-agent-builder — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

plugins/ai-adk-development/skills/adk-agent-builder/SKILL.md · 72 lines

How it starts

The opening of the file, as written. The whole thing — 72 lines — stays where its author put it; the contents beside it link to each section on GitHub.

ADK Agent Builder

Read only the reference that matches the task. Loading the whole tree costs context and buries the part that matters.

Every API below was checked against google-adk 2.6.2. If a symbol is missing at runtime, read the source under src/google/adk/ rather than guessing a neighbouring name.

Start here

Task	Reference
First agent, environment, `adk` CLI	getting-started.md
Which import path is the canonical one	import-paths.md
The rules that cause most runtime failures	best-practices.md

Building blocks

tool-catalog.md — function tools, MCP, OpenAPI, Google API toolsets, built-in tools, custom BaseTool and BaseToolset.
function-nodes.md — plain functions as nodes: parameter resolution, generators, node_input typing rules.
llm-agent-nodes.md — an LlmAgent used as a workflow node: output types, instruction templates, output_schema, auto-wrapping behavior.
task-mode.md — mode='task' and mode='single_turn' delegation with schema-validated input and output.

Graph orchestration

routing-and-conditions.md — routed edges, dict routing maps, default routes, self-loops, revision loops.
parallel-and-fanout.md — fan-out edges, JoinNode fan-in, parallel_worker=True list processing.
dynamic-nodes.md — scheduling nodes at runtime with ctx.run_node() and imperative workflow construction.
human-in-the-loop.md — RequestInput, resume behavior, resumable vs replayed sessions.
advanced-patterns.md — nested workflows, retries, custom BaseNode subclasses, graph validation rules.
multi-agent.md — chat-transfer hierarchies, and the deprecated SequentialAgent / LoopAgent / ParallelAgent shells that Workflow replaces.

Read the full file on GitHub · 72 lines

Files

What ships with it

18 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

yesterday First seen · 72 lines · 177 tokens per session scan A 5690ecc21fa4

Subscribe to this mod's changes

adk-agent-builder is a skill published in the GitHub repository joao-aires/agent-skills-public (2 stars, last pushed yesterday), licensed MIT. It adds 177 tokens to every session and 884 once invoked, about $0.0007 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 100% identical to adk-agent-builder, differing in 0 lines, and is treated as a copy.

Building agents Testing

research-engineer

An uncompromising Academic Research Engineer. Operates with absolute scientific rigor, objective criticism, and zero flair. Focuses on theoretical correctness, formal verification, and optimal implementation across any required technology.

davila7/claude-code-templates · 43 tokens

tika-eval-compare

Compare extracts from two Tika builds over a corpus to detect regressions in content, encoding, exceptions, and embedded-document handling. Use for "compare before/after extracts", "eval this change against the corpus".

apache/tika · 50 tokens

cua-driver

Use Cua Driver for desktop or browser tasks that are awkward or unavailable through Bash/APIs, or when the user explicitly wants GUI interaction: app testing, visual bug reproduction, form filling, calendar entry, screenshots, and demo recording. Also covers Cua setup; not OpenAI Codex Computer Use or web research.

davidondrej/skills · 68 tokens

adk-agent-builder