Add executable doc tests to agentgateway documentation guides using the doc test framework. Use when the user asks to "add doc tests", "add tests to a guide", "add tests to a topic", mentions "YAMLTest", or is working on quickstart guides, standalone binary guides, or Kubernetes doc pages that should generate runnable scripts from code blocks.
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Add executable doc tests to agentgateway documentation guides using the doc test framework. Use when the user asks to "add doc tests", "add tests to a guide", "add tests to a topic", mentions "YAMLTest", or is working on quickstart guides, standalone binary guides, or Kubernetes doc pages that should generate runnable scripts from code blocks.
version
1.0.0
Doc test guides skill
Use this skill when adding tests to documentation guides in the agentgateway/website repo so that code blocks and hidden steps are assembled into runnable scripts. The canonical reference is scripts/TEST_FRAMEWORK.md. This skill summarizes the workflow and gotchas for guides (especially standalone/quickstart).
When to use
Adding a new test scenario to a guide for the agentgateway standalone or agentgateway on Kubernetes open source docs.
Planning which files to change and how to tag paths for a doc test.
Test metadata lives on the content page (e.g. content/docs/standalone/main/quickstart/llm.md) in YAML front matter under test:.
Path tags and hidden blocks live in the content that gets inlined. If the content page only has {{< reuse "agw-docs/..." >}}, the real body is in assets — add paths="..." and {{< doc-test >}} in the asset file, not the content wrapper.
Critical: Most Kubernetes topic pages (e.g. content/docs/kubernetes/latest/resiliency/timeouts/request.md) are thin wrappers that only contain {{< reuse "agw-docs/pages/..." >}}. Always place doc-test blocks in the reuse file (assets/agw-docs/pages/...), never in the content wrapper. This way both latest and main versions automatically inherit the tests — you only need to add them once.
Extractor resolves {{< reuse "..." >}} from assets/, so the script is built from the expanded content. Reference the content file in test: sources; the extractor will follow reuse.
Block order: Selected blocks are emitted in document order (by file and start_line). Hidden blocks (e.g. "start server in background") must appear before any visible block that depends on them (e.g. curl). The extractor sorts selected blocks by (file_path, start_line) so hidden blocks are not deferred to the end.
Workflow for adding a test to a guide
1. Identify content and asset files
Content file: The doc page that will have test: in front matter (e.g. content/docs/standalone/main/quickstart/llm.md).
Asset file(s): Where the guide body lives. If the content page is only {{< reuse "agw-docs/standalone/quickstart/llm.md" >}}, the asset is assets/agw-docs/standalone/quickstart/llm.md. Add path tags and doc-test blocks in the asset. Never add {{< doc-test >}} blocks to the thin content wrapper — they will only apply to that one version and won't be visible to the extractor that processes the reuse expansion.
Note: The main directory contains docs for the development version, while latest contains the current stable release. Tests can be added to either or both, depending on which version the feature is available in.
2. Trace prerequisites
Follow the guide's Before you begin (or equivalent). For Kubernetes guides, chain back to install/setup (e.g. helm → gateway → sample-app → feature).
For standalone guides there may be no doc prerequisites (e.g. "install the binary" is just a block on the same page).
3. Tag runnable blocks with paths
Add {paths="<name>"} to the info string of every fenced block that should run in the test (e.g. ```sh {paths="llm"}).
Only sh/bash/shell/yaml/yml are extracted. Blocks without paths= are skipped when skip_tabs_without_paths is true.
Tabbed content: Use different paths per tab (e.g. {paths="httpbin,httpbin-linux"} and {paths="httpbin-macos"}) so the scenario can pick one.
Multiple paths must be comma-separated — both in fenced block info strings ({paths="a,b"}) and in {{< doc-test paths="a,b" >}} shortcodes. The extractor splits on ,, so space-separated values (e.g. paths="a b") are treated as a single path name and will never match — causing the block to be silently excluded from the generated script. This is especially dangerous for shared setup blocks (e.g. "install binary") that need to run for multiple scenarios.
Display-only YAML blocks: Some pages show YAML configs as plain display blocks (no cat <<'EOF' shell wrapper), unlike LLM guides that wrap configs in shell commands. You can't tag a display-only YAML block with paths= because it isn't a runnable shell command. Instead, add a hidden{{< doc-test >}} block that writes the config with cat <<'EOF' > config.yaml. See content/docs/standalone/main/mcp/mcp-authz.md for an example.
External service dependencies: When a config example depends on an external service that can't be trivially stood up in the test (e.g. Keycloak on port 9000, a custom OIDC provider), skip that example and only test self-contained ones. It's better to test one example well than to skip the entire page.
4. Long-running processes (standalone binary)
The guide may show "run agentgateway" in the foreground. For the generated script, the process must run in the background so the script can continue (e.g. curl, YAMLTest).
Add a hidden{{< doc-test paths="<name>" >}} block that runs the server in the background and cleans up, e.g.:
agentgateway -f config.yaml &
AGW_PID=$!
trap 'kill $AGW_PID 2>/dev/null' EXIT
sleep 3
Do not add a path to the visible "run agentgateway" block so it is not included in the script; only the hidden block is.
5. Env vars and placeholders
Shell-safe placeholders: Unquoted <placeholder> can be interpreted as redirection. Use quotes or a default, e.g. export OPENAI_API_KEY='<your-api-key>' or export OPENAI_API_KEY="${OPENAI_API_KEY:-<your-api-key>}".
Optional real value: Use "${VAR:-placeholder}" so the test can pass when the var is set (e.g. in CI or user's shell) and still run with a placeholder when not set.
6. Add test front matter on the content page
---title:...test:<scenario-name>:-file:${versionRoot}/quickstart/<page>.md# same-version prereqpath:<path-name>-path:<path-name># file: omitted -> this page itself---
Write file: values version-relative so a page can be copied between main and latest with no front-matter edits:
Omit file: when the source is the page that declares the test — it defaults to the declaring page.
Use ${versionRoot}/... for prerequisites in the same version (e.g. ${versionRoot}/quickstart/install.md). ${versionRoot} expands to the version dir of the page declaring the test (content/docs/kubernetes/main, .../latest, etc.); ${version} expands to just the segment (main/latest).
Use a literal path only when an entry must point at a different version on purpose.
Token resolution covers the kubernetes and standalone sections; a file: that doesn't match the content/docs/<section>/<version>/ layout is left as-is.
Pages with no testable content (no code blocks, landing pages, concept pages, _index.md files without ordered steps, etc.) should be marked with test: skip instead of a scenario dict. This counts the page as covered in the test coverage report without generating any test cases:
---title:Abouttest:skip---
Before marking a page test: skip, consider whether the content could become testable. The table below summarizes what it would take for each category of "non-runnable" content. If the effort is low (content-only changes), prefer making the page testable over skipping it.
Content type
Why it seems non-runnable
Path to testable
Change needed
Display-only YAML configs with placeholders (e.g. Auth0, provider configs)
Add hidden {{< doc-test >}} blocks that write self-contained configs via cat <<'EOF' > config.yaml, start the server, and validate with agentgateway --validate or a YAMLTest health check. Skip examples that require real external services (IdPs, cloud APIs) and test only the self-contained subset
Content only
Client config snippets (e.g. Claude Desktop JSON, VS Code settings)
Can't run the client in CI
Add hidden blocks that write the JSON to a file and validate syntax with jq . config.json. Catches typos and structural errors without proving the integration works end-to-end
Content only
Conceptual/about pages (pure prose, no code)
No code to run
Add a minimal "try it" example at the bottom that demonstrates the concept with a working config + assertion. This is a content strategy decision — if the page's purpose is purely explanatory, test: skip is appropriate
Content decision
Index/hub pages (_index.md with card links)
No code, only navigation
These are legitimately test: skip. The only possible validation is confirming card link targets exist, which would be a separate link-checking CI job (not a doc test)
Script change (separate job)
Key principle: The existing framework already supports every content type except pure link validation. Most "non-runnable" pages can become testable through content changes alone — adding hidden {{< doc-test >}} blocks that write configs, start services in the background, and run lightweight assertions.
Because the example above uses ${versionRoot} and omits file: for the declaring page, the same front matter works under latest/ without changes. Only when you deliberately mix versions do you write a literal path:
---title:...test:<scenario-name>:-file:content/docs/standalone/latest/quickstart/<page>.md# literal: pin a specific versionpath:<path-name>---
Prefer version-relative file: values (see above). List sources in dependency order if chaining (install → … → feature).
One scenario can list only the current page with one path if the guide is self-contained.
For Kubernetes docs, prerequisite files often come from latest (e.g. content/docs/kubernetes/latest/quickstart/install.md) while the feature page may be in main or latest.
7. Optional: YAMLTest assertions
For HTTP checks (e.g. "GET returns 200"), add a hidden {{< doc-test paths="<name>" >}} block with a YAMLTest snippet:
YAMLTest -f - <<'EOF' and a test entry with http: and expect:.
Place it after the block that starts the server (so after the hidden "start in background" block in the doc).
Supported expect: properties (all are direct children of expect:, at the same indentation level):
statusCode: <number> — assert HTTP response status code
headers: — list of {name, comparator, value} entries for response header assertions (case-insensitive)
bodyJsonPath: — list of {path, comparator, value} entries using JSONPath expressions against the response body
Do not use jsonPath — the correct property name is bodyJsonPath. Using jsonPath causes /expect: unknown property "jsonPath" schema validation errors.
MCP endpoint testing
MCP uses JSON-RPC over HTTP, so YAMLTest works for MCP endpoints, but the request format differs from REST. To test that an MCP endpoint is up and accepting connections, send an initialize request:
For deeper assertions (e.g. verifying tools/list returns only authorized tools), you would need to capture the mcp-session-id from the initialize response and pass it as a header in subsequent requests. The authorization tutorial (content/docs/standalone/main/tutorials/authorization/_index.md) shows the full curl-based MCP session flow.
For Kubernetes tests, use ${INGRESS_GW_ADDRESS} as the host in the URL (e.g. url: "http://${INGRESS_GW_ADDRESS}:80/get"). Never use kubectl port-forward in visible blocks — tests containing kubectl port-forward are automatically failed without running.
Host headers must not include a port — use host: "example.com", not host: "example.com:80". The gateway's hostname matching is strict: including the port causes no route match, and agentgateway resets the TCP connection (ECONNRESET) rather than returning an HTTP error response.
Response body CEL expressions require uncompressed responses. YAMLTest uses axios, which sends Accept-Encoding: gzip, deflate, br by default. If a test asserts on a response header computed from a json(response.body) CEL expression (e.g. string(json(response.body).model)), the upstream may return a compressed body that agentgateway cannot parse, causing the CEL expression to fail silently and the header to never be set. Fix by adding accept-encoding: identity to the YAMLTest http.headers to force an uncompressed response. This only affects test requests — curl and most API clients do not request compression by default, so user-facing examples work without the header.
Data plane warmup for new hostnames
When a test creates a new HTTPRoute with a hostname that was not previously registered (e.g. match.example), agentgateway-proxy (a Rust/hyper proxy, not Envoy) goes through two distinct phases before it can serve the new route. Kubernetes resource wait assertions (Accepted=True, ResolvedRefs=True) only reflect control plane state and pass in ~50ms — they do not guarantee the data plane has applied the new config yet.
Two-phase proxy behavior:
Phase 1 (~120s): The proxy is not yet aware of the new hostname. Every connection is immediately reset (ECONNRESET in < 1ms). Because the reset is instant (not a timeout), curl --max-time 5 iterations each cost ~2s (immediate failure + 2s sleep). 60 iterations × 2s = 120s max for this phase.
Phase 2 (last few seconds): The proxy receives the xDS config update and holds incoming connections while applying it (due to header_read_timeout = 10 minutes). Each connection hangs 4–26s before being reset. This is brief but can still fail a YAMLTest entry.
Phase 3: Proxy serves the route normally.
Symptom: Wait assertions pass in under a second. The curl warmup loop runs for ~2 minutes (Phase 1), then the first YAMLTest HTTP entry hangs 4–26s and fails with read ECONNRESET (Phase 2). Adding retries: 3 (without a warmup loop) makes Phase 2 far worse — each retry hangs for the full duration (observed: 4 × 107s ≈ 429s).
Fix: Use both a curl warmup loop (covers Phase 1) and retries: 1 on the first HTTP test entry (covers Phase 2):
{{< doc-test paths="<scenario-name>" >}}
for i in $(seq 1 60); do
curl -s --max-time 5 -o /dev/null "http://${INGRESS_GW_ADDRESS}:80/get" -H "host: <new-hostname>" && break
sleep 2
done
{{< /doc-test >}}
{{< doc-test paths="<scenario-name>" >}}
YAMLTest -f - <<'EOF'
- name: <scenario> - first HTTP assertion
retries: 1
http:
url: "http://${INGRESS_GW_ADDRESS}:80"
path: /get
method: GET
headers:
host: "<new-hostname>"
source:
type: local
expect:
statusCode: 200
EOF
{{< /doc-test >}}
The curl loop exits as soon as the proxy returns any HTTP response (even 404) — that signals Phase 1 is over. retries: 1 on the YAMLTest entry absorbs the Phase 2 hold (one retry after a 4–26s hang). Do not use retries: 3 or higher without the warmup loop — it amplifies the total wait time dramatically.
When this applies: Any test that creates an HTTPRoute with a hostname not already registered in the proxy. Tests that update or replace an existing HTTPRoute from the prereq chain (same name, same namespace) don't trigger this — the virtual host is already wired up.
How to spot it in advance: Compare the HTTPRoute name in the feature page's kubectl apply blocks vs. the HTTPRoute names created in the prereq chain. If the feature creates a new name (e.g. httpbin-match for match.example) that isn't in the prereqs, add the warmup loop + retries: 1. If it overwrites an existing prereq-chain HTTPRoute (same name), skip it.
For cleanup blocks tagged with a specific path, add --ignore-not-found to kubectl delete commands only when the page has multiple test scenarios and the cleanup block is shared across them (tagged with multiple paths like paths="scenario-a,scenario-b"). In that case, a single scenario may only create a subset of the resources the cleanup tries to delete. When a page has only one test scenario, --ignore-not-found is unnecessary because every resource in the cleanup was created by that scenario.
8. Validate YAML code blocks
Before generating, review any yaml/yml fenced blocks tagged with paths= to catch indentation bugs that cause silent misconfigurations:
List items under a mapping key: - item: followed by - child: at the same dash column means child is a sibling, not a child. Indent - child: 2 more spaces to nest it properly.
Common hotspot: rules[].filters in HTTPRoute specs. A misindented - type: RequestRedirect becomes a second rule instead of a filter entry, resulting in a route with no filter and no backend — the gateway resets the connection (ECONNRESET) instead of returning the expected HTTP response.
Quick check: For any key:\n - subkey: pattern, verify the - of the list item is indented at least 2 spaces past the start of key.
9. Generate and verify
From the repo root directory: python3 scripts/doc_test_run.py --repo-root . --generate-only
From repo root: python3 scripts/doc_test_run.py --generate-only
Inspect out/tests/generated/*.sh: order of steps, no unresolved shortcodes, env vars and backgrounding correct.
Run a script manually, e.g. bash out/tests/generated/<script-name>.sh (standalone tests do not use a kind cluster; use --generate-only and run the script in an env that has the binary/Docker/etc.).
10. Report what is tested and what is not (required)
Every time you add or update a doc test, produce a coverage summary for the page: a list of what the test validates from the visible content, and a list of what it does not validate, each with a one-line reason. This makes coverage gaps explicit instead of letting a passing test imply the whole page is covered.
Do this in two places:
In the test, as a {{< doc-test >}} comment block at the top of the test's hidden setup (the comment is not rendered on the page). Keep it current when you change assertions. Example shape:
{{< doc-test paths="<scenario>" >}}
# WHAT THIS TEST VALIDATES:
# * <thing> — <which content block / panel / endpoint it covers>
# WHAT THIS TEST DOES NOT VALIDATE (and why):
# * <thing> — <reason: UI-only step / external dependency not stood up /
# requires traffic or config this page does not include / display-only example / etc.>
{{< /doc-test >}}
To the user, as a short two-list summary in your reply.
Write each "not tested" reason from a fixed set of causes so the gap is actionable:
UI-only step — the doc instructs clicking through a web UI (no scriptable equivalent), so the test uses an API call as a proxy or skips it.
Display-only block — the block is illustrative (PromQL query, a version: '3' compose file) and isn't a self-contained runnable command.
External dependency — needs a service the test can't stand up (real IdP, cloud API, LLM provider key).
Requires config/traffic the page omits — the metric/log/trace only appears with setup that lives on a different page (e.g. a tracing policy, an OTLP access-log policy, LLM/MCP traffic).
Different layer — e.g. backend pod readiness is checked but not that data is actually stored; the asserted metric exists but the dashboard panel's render isn't verified.
Base both lists on what you actually confirmed on a run, not on what you intended to cover. If an assertion was dropped because it failed (and the failure is a content/product gap, not a test bug), it belongs in "not tested" with the reason — see step 11.
11. When a test fails: fix the test or fix the content?
When a test fails, determine where the bug lives before changing anything. There are two distinct cases:
Case 1: Test bug, content is correct
The hidden {{< doc-test >}} block has a mistake — wrong assertion, missing retry, bad YAMLTest schema property, missing env var setup — but the visible documentation accurately describes what the product does. Fix only the test. The customer-facing content stays as-is.
Examples:
YAMLTest wait.target includes an unsupported property like apiVersion → remove the invalid property from the hidden block.
A shell variable (e.g. ANTHROPIC_API_KEY) is referenced in a tagged block but set in an untagged visible block → add a hidden {{< doc-test >}} block that exports the variable with a placeholder default.
A config_dump assertion needs more retries because the data plane takes time to propagate → increase retries in the hidden block.
Case 2: Content bug, test is revealing it
The visible documentation — kubectl apply blocks, example output, curl commands, or explanatory text — shows something that does not actually work as described. The test is correctly catching a real problem. Fix the content first, then update the test to match the corrected content. Do not silently weaken or remove test assertions to hide content bugs.
Examples:
A documented CEL expression (e.g. json(response.body).model) silently fails, so a response header the docs promise never appears → the visible kubectl apply block and example output are misleading readers. Flag this for a content fix. Don't just remove the assertion.
An example YAML block has a wrong apiVersion or misindented field that causes the resource to behave differently than described → fix the visible YAML, then update the test.
An example curl command shows a response that the product doesn't actually return → fix the example output.
How to tell the difference
Ask: "If a customer follows the visible instructions exactly, will they get the documented result?"
Yes → Case 1. The test setup is wrong.
No → Case 2. The content needs to be corrected. Raise the issue with the content owner if you can't determine the correct fix yourself.
When in doubt, flag the failure to the user rather than silently adjusting the test. A weakened assertion that hides a content bug is worse than a failing test.
Checklist (quick)
Path tags and {{< doc-test >}} blocks added in the asset file(s) (assets/agw-docs/...), not in the content wrapper files — even if multiple content files (e.g. latest/ and main/) reuse the same asset.
Multiple paths in paths="..." are comma-separated, not space-separated — paths="a,b" ✓, paths="a b" ✗ (spaces make the whole string a single path, silently excluding the block).
If the guide has a long-running server, a hidden doc-test block starts it in the background (and optional trap/sleep); visible "start server" block has no path.
Placeholders in shell blocks are quoted or use ${VAR:-default} so the script has no syntax errors.
test: front matter on the content page lists the right file and path; file path is the content path (extractor follows reuse). For pages with no testable content (index pages, no code blocks), use test: skip instead — counts toward coverage without generating test cases.
file: values are version-relative (${versionRoot}/..., or omitted for the declaring page) so copying a page between main and latest needs no front-matter edits. Use a literal path only to point at a different version on purpose.
Prerequisite file: paths come from the guide's actual Before you begin links — don't guess; check the links to confirm exact paths.
No kubectl port-forward in any visible block — replace with YAMLTest HTTP assertions using ${INGRESS_GW_ADDRESS}.
Host headers in YAMLTest http.headers use bare hostnames — no port suffix (e.g. host: "example.com", not host: "example.com:80"). Including a port causes ECONNRESET, not an HTTP error.
If the test creates an HTTPRoute with a hostname not already in the prereq chain, use the two-phase warmup fix: (1) add a curl warmup loop {{< doc-test >}} block before the YAMLTest block (for i in $(seq 1 60); do curl -s --max-time 5 ... && break; sleep 2; done) to cover Phase 1 (~120s of immediate resets), AND (2) add retries: 1 to the first HTTP assertion in YAMLTest to absorb Phase 2 (4–26s hold then reset). Do not use retries: 3 or higher without the warmup loop — it multiplies the total wait time.
Cleanup blocks on multi-scenario pages (where the cleanup is shared across paths) use --ignore-not-found on kubectl delete commands. Single-scenario pages do not need it.
YAMLTest expect: uses bodyJsonPath (not jsonPath) for response body assertions; all keys under expect: are at the same indentation level.
YAML code blocks tagged with paths= have correct indentation — list items nested under a mapping key (e.g. filters, matches, rules) must be indented 2+ spaces past the key, not at the same level.
Display-only YAML blocks (no shell wrapper) are not tagged with paths= — use a hidden {{< doc-test >}} block with cat <<'EOF' > config.yaml instead.
For MCP endpoint tests, use a JSON-RPC initialize request (not a simple GET) — see the MCP endpoint testing section above.
Examples that depend on external services (auth servers, rate limit services) that can't be stood up in the test are skipped — only self-contained examples are tested.
Generated script order makes sense (server before curl/YAMLTest); regenerate after extractor changes if needed.
Optional YAMLTest in a hidden block for HTTP or other assertions.
When fixing a failing test, verified whether the bug is in the test or in the customer-facing content. If the content is wrong, fix the content first — don't silently weaken assertions.
Produced a coverage summary (what is tested / what is not, with a reason for each gap) — both as a {{< doc-test >}} comment block in the test and in the reply to the user. See step 10.
