This is a 10-part series sharing how Apidog developed Apidog CLI, a command-line tool for API testing and API lifecycle management. Read in order or jump to any post that interests you:
| Title | Focus | |
|---|---|---|
| 1 | We Built 126 MCP Tools. But It Is Not the Best Solution for Agent | Problem discovery |
| 2 | Why We Developed Brand-new Apidog CLI | Architecture development |
| 3 | The Golden Rule: CLI Produces Facts, Model Acts on Facts | Core philosophy |
| 4 | agentHints: Teaching CLIs to Talk to Agents |
Structured output |
| 5 | SKILL: Shipping Operational Experience as Code | Operational experience |
| 6 | The Numbers Don't Lie: 30% Fewer Tool Calls, 25% Fewer Tokens | Quantitative results |
| 7 | From PRD to Testing Loop: A Complete Agent Workflow with Apidog CLI | Practical tutorial |
| 8 | Why CI/CD Compatibility Is Non-Negotiable for Agent Tools | DevOps perspective |
| 9 | AI Branch: Safer Project Changes with AI Agents | Security layer |
| 10 | Spec-First Was Yesterday. Welcome to Skill-First. | Vision & future |
A SKILL is not just a command reference. It's an operating guide for AI Agents: when to use a command, which comes first, what fields shouldn't be guessed, when to validate, when to read back.
CLI Alone Isn't Enough
CLI commands give an Agent execution power.
But power without judgment leads to problems:
| CLI Power | Risk Without Judgment |
|---|---|
| Create test case | Creates in wrong project |
| Update test scenario | Updates without reading back |
| Import steps | Imports without checking existing structure |
| Run tests | Runs without validating changes |
Agents need more than commands. They need operating judgment.
What Is SKILL?
A SKILL is an operating guide written for AI Agents.
It's not:
- A simple command list
- A reference manual
- A help page
It is:
| SKILL Content | Purpose |
|---|---|
| When to use a command | Task type → command mapping |
| Which command comes first | Sequence guidance |
| What fields should not be guessed | Safety boundaries |
| When to validate | Quality gate placement |
| When to read back | Verification timing |
| When to run tests | Confirmation workflow |
SKILL gives Agents operating judgment.
Installation
SKILL is a companion to Apidog CLI:
# Install SKILL for your AI Agent
apidog skill installThis installs 8 companion Skills that help Agents understand:
- CLI command semantics
- Resource structures
- Task workflows
- Error handling
- Verification patterns
Why SKILL Matters: Hidden Workflows
The Agent still needs to know how tasks should be decomposed into cross-business execution flows.
This experience cannot be:
- Comprehensively written into tool descriptions (would consume too much context)
- Scattered in chat context (would be lost between sessions)
- Memorized by the model (product-specific, not general knowledge)
Hidden workflows and "business pitfalls" require explicit guidance.
Example: Test Scenario Maintenance
Consider maintaining a complex test scenario.
Wrong approach (Agent hand-writes from scratch):
Agent: "I'll create the test scenario structure manually"
Agent: Writes complete steps array with assertions, extractors, processors
Result: Field errors, wrong comparators, missing required fields
CLI: Rejects write or creates incomplete scenarioCorrect approach (encoded in SKILL):
| Step | Why |
|---|---|
| 1. Import existing steps from endpoints or test cases | Don't hand-write complex structures |
| 2. Read back complete structure | See actual imported format |
| 3. Make local modifications | Work with accurate base |
| 4. Validate before update | Catch errors locally |
| 5. Run scenario | Verify behavior |
SKILL doesn't just say "there's a test-scenario update command."
It says:
"Complex scenarios are not suitable for hand-writing complete structures from scratch. A more stable path is to first import existing endpoint or case steps, then read back the complete structure, and finally make local modifications."
The Commands Behind SKILL Guidance
Here are the actual commands SKILL guides Agents to use:
# Step 1: Import steps from endpoints
apidog test-scenario import-steps <scenarioId> --project <projectId> \
--source endpoint --ids <endpointIds> --sync manual
# Step 2: Read back with full detail
apidog test-scenario get <scenarioId> --project <projectId> \
--with-case-detail
# Step 3: Update specific parts (Agent generates update JSON)
# Step 4: Validate before update
apidog cli-schema validate test-scenario-update --file ./scenario-update.json
# Step 5: Execute update
apidog test-scenario update <scenarioId> --project <projectId> \
--file ./scenario-update.json
# Step 6: Run verification
apidog run --project <projectId> --test-scenario <scenarioId>SKILL tells the Agent when to use each command and why.
Key Insight: get--with-case-detail
SKILL emphasizes:
"Use get--with-case-detail to get the real structure, not imagine the case inside steps."Why this matters:
Without get--with-case-detail |
With get--with-case-detail |
|---|---|
| Steps show IDs only | Steps show full case structures |
| Agent doesn't know internal format | Agent sees actual assertion/extractor format |
| Agent guesses field names | Agent works from real examples |
Getting real structure prevents imagination-based updates.
Evolvability: SKILL Can Change
Apidog SKILL is evolvable and versionable operational experience.
Why This Matters
| Challenge | SKILL Solution |
|---|---|
| CLI commands change | SKILL can be updated to match |
| Users have personalized workflows | SKILL can be customized |
| New product features | SKILL can be extended |
| Workflow improvements | SKILL can be refined |
How It Works
Agents are granted write permissions to SKILL.
If SKILL falls behind or becomes hard to use:
- Agent can modify it
- Agent can suggest improvements
- SKILL evolves through usage
SKILL is not frozen documentation. It's living operational code.
The Compatibility Layer
We learned this from real bugs:
Problem discovered:
Some scenario steps, during secondary updates, had outer steps updated successfully, but internal HTTP cases were not correctly updated.
Root cause:
- Internal case update markers needed special handling
- Agents didn't know about these markers
- Product semantics required specific flags
Solution:
- Compatibility logic put into CLI
- CLI handles internal markers automatically
- Users and Agents don't need to know internal details
The constraint meaning is layered into SKILL:
SKILL tells the Agent to use the right commands. CLI handles the product semantics behind those commands. The Agent doesn't need to understand internal markers.
On-Demand Loading
SKILL follows the same principle as cli-schema:
Complexity should be absorbed by execution and documentation, not fully exposed to the model.
| Alternative | Problem |
|---|---|
| Load all SKILL into context | Token burden |
Put all rules in --help |
Competes for attention |
| Write into prompt | Cannot be updated |
SKILL approach:
- Agent warms up SKILL on demand
- SKILL loaded when task type is identified
- Only relevant workflow guidance enters context
SKILL vs. Documentation
| Documentation | SKILL |
|---|---|
| For humans to read | For Agents to execute |
| Explains what commands do | Explains when to use them |
| Static reference | Dynamic workflow |
| Comprehensive | Task-focused |
| External to Agent | Integrated with Agent |
The 8 Companion Skills
Apidog provides 8 companion Skills:
| SKILL | Coverage |
|---|---|
| Project management | Projects, metadata, resources |
| API design | Endpoints, schemas, definitions |
| Environment management | Environments, variables |
| Test case creation | Single-endpoint tests, assertions |
| Test scenario management | Multi-step tests, import, update |
| Test suite organization | Grouping, execution |
| Import/export workflows | Data migration, backup |
| CI/CD integration | Pipeline commands, reports |
Each SKILL contains:
- Task type identification
- Command sequence guidance
- Field safety boundaries
- Validation checkpoints
- Verification patterns
What's Next
Now that we've established all three core components:
- cli-schema validate — Quality gate
- agentHints — Next-step navigation
- SKILL — Workflow judgment
The next question is:
Does this actually work? What are the numbers?
In Part 6, The Numbers Don't Lie: 30% Fewer Tool Calls, 25% Fewer Tokens, we'll share quantitative results from our internal comparisons—and explain where the savings come from.
Key Takeaways
- CLI gives execution power; SKILL gives operating judgment
- SKILL is an operating guide, not a command reference
- Hidden workflows require explicit guidance
- Import steps → read back → update locally is safer than hand-writing
--with-case-detailprevents imagination-based updates- SKILL is evolvable—Agents can modify it
- CLI absorbs product semantics, SKILL guides workflow
- On-demand loading prevents context burden
Download Apidog to design, mock, test, and document APIs in one workspace. Learn more about Apidog CLI for command-line API testing, CI automation, and AI Agent workflows.



