generate-from-typespec

Generate From TypeSpec Skill

Compiles a TypeSpec specification using the local @typespec/http-client-python emitter and generates Python SDK code. Supports both branded (@azure-tools/typespec-python) and unbranded (@typespec/http-client-python) generation.

Inputs

The caller must provide:

1. Spec path — either:
   • A local file path to a .tsp entry point (e.g., client.tsp, main.tsp)
   • A raw GitHub URL pointing to a TypeSpec project directory or file (e.g., https://github.com/Azure/azure-rest-api-specs/tree/main/specification/.../Foundry/src/sdk-service-agentserver-contracts/client.tsp)
2. Flavor — azure (branded) or unbranded. If not provided, ask the user.
3. Emitter output directory — the full resolved path where generated code should be written (e.g., ~/Desktop/github/azure-sdk-for-python/sdk/agentserver/azure-ai-agentserver-responses). If not provided, ask the user.
4. Additional options (optional) — any extra key=value emitter options the user wants applied on top of the tspconfig options. These override tspconfig values if there's a conflict (e.g., generate-typeddict=false).

Workflow

Step 1: Resolve the spec path

If the input is a GitHub URL:

1. Parse the URL to extract owner, repo, ref (branch/commit), and path.
2. Check if the repository is cloned locally (look under common locations like ~/Desktop/github/<repo-name>, ~/<repo-name>, etc.).
3. If found locally, check out the correct ref/commit if needed:

   cd <local-repo>
   git fetch origin <ref>
   git checkout <ref> -- <path-to-spec-dir>/
   

4. If not found locally, ask the user where the repo is cloned, or offer to clone it.

If the input is a local path:

Verify the file/directory exists. If the path points to a directory, look for client.tsp or main.tsp as the entry point.

Step 2: Locate and parse tspconfig.yaml

Look for tspconfig.yaml in the same directory as the spec entry point, then walk up parent directories until one is found.

# Starting from the spec file's directory, search for tspconfig.yaml
current_dir="<spec-dir>"
while [ "$current_dir" != "/" ]; do
  if [ -f "$current_dir/tspconfig.yaml" ]; then
    echo "Found: $current_dir/tspconfig.yaml"
    break
  fi
  current_dir=$(dirname "$current_dir")
done

Step 3: Extract Python emitter options from tspconfig.yaml

Parse the tspconfig.yaml and extract the options block for the Python emitter. The emitter may appear under either name:

Flavor	Emitter key in tspconfig.yaml
Branded	@azure-tools/typespec-python
Unbranded	@typespec/http-client-python

Important cross-flavor rule: If the user requests a different flavor than what's in the tspconfig, carry over ALL options from the tspconfig's Python emitter block. For example:

• tspconfig has options under @azure-tools/typespec-python but user wants unbranded → use all those options, but emit under @typespec/http-client-python
• tspconfig has options under @typespec/http-client-python but user wants branded → use all those options, but emit under @azure-tools/typespec-python

If no Python emitter options exist in the tspconfig at all, ask the user for:

• emitter-output-dir (required — where to write the generated code)
• package-name (required)
• namespace (optional — omit to let @clientNamespace decorators resolve naturally)

Step 4: Determine the flavor

Use this precedence:

1. If the user explicitly stated azure or unbranded, use that.
2. If the tspconfig has a flavor option set, mention it to the user and confirm.
3. If the tspconfig only has one Python emitter key, infer:
   • @azure-tools/typespec-python → azure
   • @typespec/http-client-python → unbranded
4. If still ambiguous, ask the user:

   "Should I generate as branded (azure flavor) or unbranded?"

Step 5: Find the TypeSpec compiler

Look for the tsp CLI in the spec repo's node_modules:

# Check spec repo root for compiler
< spec-repo-root > /node_modules/@typespec/compiler/cmd/tsp.js

If not found, fall back to the global tsp command, or check the typespec monorepo's compiler:

~/Desktop/github/typespec/packages/compiler/cmd/tsp.js

Step 6: Construct and run the compile command

Build the tsp compile command using:

• Entry point: The resolved .tsp file from Step 1
• --emit: Always the local emitter path: ~/Desktop/github/typespec/packages/http-client-python
• --option flags: One for each option from the tspconfig, prefixed with the local emitter name @typespec/http-client-python (regardless of what the tspconfig called it). Any additional options provided by the user are appended last and override tspconfig values if there's a conflict.

Template:

< tsp-cli-path > compile < entry-point.tsp > --emit ~/Desktop/github/typespec/packages/http-client-python \
  --option "@typespec/http-client-python.<key1>=<value1>" \
  --option "@typespec/http-client-python.<key2>=<value2>" \
  ...

Option mapping rules:

tspconfig key	CLI --option key	Notes
emitter-output-dir	emitter-output-dir	Resolve {output-dir}, {service-dir} variables
package-mode	package-mode	Usually dataplane or mgmt
package-name	package-name
namespace	namespace	Omit if not in tspconfig — see note below
api-version	api-version
flavor	flavor	Set to azure for branded, omit for unbranded
generate-test	generate-test
generate-sample	generate-sample
models-mode	models-mode	e.g., dpg, msrest, typeddict
Any other option	Pass through as-is

Namespace note: Do NOT pass --namespace unless it is explicitly set in the tspconfig or by the user. When omitted, the emitter lets TCGC resolve @clientNamespace decorators correctly. Passing a namespace when @clientNamespace is used in the spec can cause incorrect directory nesting.

emitter-output-dir: Always use the value provided by the user (Input #3). Ignore the emitter-output-dir from the tspconfig — it typically contains unresolvable template variables like {output-dir} and {service-dir}.

Step 7: Run the compilation

cd <spec-directory>
<constructed-compile-command>

Set a timeout of at least 180 seconds — compilation can take a few minutes.

Check the output:

• Warnings only → success
• Errors → report to the user with the full error output

Step 8: Verify and clean up

After successful compilation:

1. Show the generated directory structure:

   find < output-dir > -type d | sort
   

2. Verify the output matches expectations (e.g., TypedDict-only if models-mode=none).

3. If the generation overwrote files in an existing package, warn the user and offer to revert non-generated files:

   cd <sdk-repo>
   git diff --name-status <package-dir>/ | grep -v "<expected-generated-path>"
   

Notes

The --namespace trap

When a TypeSpec uses @clientNamespace to map types into a different namespace, TCGC resolves the namespace. If you also pass --namespace, TCGC tries to replace the root of the @clientNamespace value with the flag, which can produce doubled prefixes like azure.azure.ai.projects.... Only pass --namespace when the tspconfig explicitly sets it.

Branded vs unbranded emitter names

The local emitter is always @typespec/http-client-python on the CLI --emit and --option flags. The flavor option controls branded behavior:

• Branded: --option "@typespec/http-client-python.flavor=azure"
• Unbranded: omit the flavor option entirely

Common additional options the user may request

User request	Option to add
TypedDict only	--option "@typespec/http-client-python.models-mode=none"
No TypedDicts	--option "@typespec/http-client-python.generate-typeddict=false"
No tests	--option "@typespec/http-client-python.generate-test=false"
No samples	--option "@typespec/http-client-python.generate-sample=false"