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.
npx agentmods add skills/elastic/integration-skills/cel-programsnpx skills add elastic/integration-skills --skill cel-programsgit clone --depth 1 https://github.com/elastic/integration-skillsWhat 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 | $0.00065 | $0.05278 |
| Opus 5 | $0.00032 | $0.02639 |
| Sonnet 5 | $0.00013 | $0.01056 |
| Haiku 4.5 | $0.00006 | $0.00528 |
Grade A, and why
cel-programs 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.
How it starts
The opening of the file, as written. The whole thing — 326 lines — stays where its author put it; the contents beside it link to each section on GitHub.
cel-programs
When to use
Use this skill when tasks include:
- creating or editing
cel.yml.hbsagent stream templates - configuring data stream manifests for the
celinput type - writing CEL programs with pagination, cursor management, or authentication
- testing or debugging a CEL program locally with mito
- setting up system tests with mock APIs for CEL-based data streams
- prototyping a new CEL-based data stream's collection logic
- any CEL or mito question, regardless of context
When not to use
Do not use this skill as the primary guide for:
- ingest pipeline processor design (
ingest-pipelines) - ECS field mapping (
ecs-field-mappings) - package scaffolding (
create-integration) - system test execution with the Elastic stack (
integration-testing→references/system-testing.md)
Mandatory workflow — mock → mito → template
This is not a suggestion. Every CEL program MUST be developed in this order. The subagent must not write cel.yml.hbs until the CEL program has been validated with mito against a running mock. Skipping steps or reordering causes failures that are hard to debug.
Do NOT write more than ~10–15 new lines of CEL before running mito. Build the program incrementally in phases (skeleton → error handling → event mapping → pagination → cursor guard), validating with mito after each phase. Writing a large program in one shot leads to cascading compilation errors that are extremely hard to debug. Follow the phased approach in references/cel-incremental-build.md.
| Step | Action | Output |
|---|---|---|
| 1. Create the system test mock | Write the elastic/stream config at _dev/deploy/docker/files/config-<stream>.yml with rules matching all API endpoints. Write test-default-config.yml. |
Mock config file, docker-compose service, test config |
| 2. Start the mock locally | stream http-server --addr=:8090 --config=... |
Running mock at http://localhost:8090 |
3. Create a plain .cel file and state.json |
Write the CEL program as a standalone .cel file. Create state.json with the same keys the future state: block will contain, but with literal test values instead of Handlebars. Point url at the local mock. |
program.cel, state.json in /tmp or working dir |
| 4. Run mito and iterate | Build incrementally per references/cel-incremental-build.md: Phase 0 skeleton → Phase 1 error handling → Phase 2 events → Phase 3 pagination → Phase 4 cursor. Run mito -data state.json -log_requests program.cel after each phase. Do not proceed until mito output is correct. |
Validated CEL program |
5. ONLY THEN write cel.yml.hbs |
Copy the working CEL expression into program: | in the Handlebars template. Replace literal test values with {{var}} references. Configure manifests. |
Final integration template |
What ships with it
20 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.
- references/builder-subagent-guidance.md 29 KB
- references/cel-auth-patterns.md 3.6 KB
- references/cel-code-style.md 22 KB
- references/cel-complexity-baselines.md 4.2 KB
- references/cel-expression.md 13 KB
- references/cel-function-reference.md 14 KB
- references/cel-idioms.md 12 KB
- references/cel-incremental-build.md 17 KB
- references/cel-pagination-patterns.md 12 KB
- references/cel-polymorphic-patterns.md 7.7 KB
- references/cel-rate-limiting.md 2.5 KB
- references/cel-system-tests.md 27 KB
- references/cel-taxonomy.md 5.2 KB
- references/cel-template-examples.md 13 KB
- references/expression-builder-subagent-guidance.md 9.1 KB
- references/mito-reference.md 15 KB
- references/reviewer-subagent-guidance.md 6.3 KB
- references/tests/map_drop.txt 369 B
- references/tests/map_merge.txt 412 B
- references/tests/map_shallow_merge.txt 534 B
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 · 326 lines · 65 tokens per session scan A 2f980d088645
cel-programs is a skill published in the GitHub repository elastic/integration-skills (15 stars, last pushed 4d ago), licensed Apache-2.0. It adds 65 tokens to every session and 5,278 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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