feat: resolve the API key from api_key= then COMFY_API_KEY, with a clear local error

[mattmillerai]

ELI-5

If you forget your API key, the SDK now tells you so the moment you build a client — and tells you which environment variable to set — instead of letting the server say 401 a round trip later. It also looks in COMFY_API_KEY for you, so you don't have to paste the key into your code at all.

What changed

A client resolves its credential once, at construction, in a fixed order:

1. the explicit api_key= argument — it always wins;
2. COMFY_API_KEY from the environment, when no argument was passed;
3. neither → MissingApiKey, raised locally, naming the environment variable.

Both sources are trimmed and a blank value counts as unset, so COMFY_API_KEY= in a shell profile and a key read from a file with a trailing newline both do the obvious thing. Both are re-read on every construction, matching how COMFY_BASE_URL already behaves.

Comfy/AsyncComfy also gain an explicit repr() — base URL plus authenticated=True|False, never the key — backed by a new ComfyLow.authenticated property. comfy_low is otherwise unchanged: it takes the key it is handed and reads no environment, because resolution is a comfy_sdk concern.

The one judgment call: step 3 applies to Comfy Cloud only

The repo already documents, and tests, a surface that legitimately has no credential — "Self-hosted ComfyUI (behind the API proxy) | Omit — no key is sent, even implicitly" in the README, locked in by tests/test_auth_headers.py. An unconditional "no key → raise" would delete that capability, so the error fires only when the resolved base URL is Comfy Cloud (the default). Point COMFY_BASE_URL at anything else and an unresolved key means exactly what it has always meant: build the client, send no credentials. The error message names COMFY_BASE_URL for precisely that reason — it redirects you to the path that still works rather than dead-ending.

Consequence worth stating plainly: a serverless deployment does require a key but is also selected by COMFY_BASE_URL, so a keyless serverless client is still a server 401, as today. The SDK cannot tell a serverless URL from a self-hosted one, and guessing wrong would deny a working configuration.

Second consequence: on the Cloud default, key resolution now runs before the transport validates client_info, so a client built with both a bad client_info and no key sees MissingApiKey first. Base-URL validation still runs first of all, since it decides whether a key is required at all.

Verification of the capability this denies

The new code path denies one thing: constructing a working keyless client against Comfy Cloud. Attempted it directly, read-only, against the live surface before shipping the dead-end:

GET https://cloud.comfy.org/api/v2/jobs/00000000-0000-0000-0000-000000000000   (no Authorization)
  -> 401 {"error":{"code":"unauthorized","message":"Missing or invalid API key. Send 'Authorization: Bearer <your comfyui- key>'."}}
HEAD https://cloud.comfy.org/api/v2/assets/by-hash/blake3:<64-hex>             (no Authorization)
  -> 401

Both a read and a probe are rejected unauthenticated, so a keyless Cloud client could only ever have produced that 401 — the change replaces a guaranteed server rejection with a local one, and does not remove any reachable capability. The surviving keyless path is exercised live in the opposite direction: test_auth_headers.py::test_no_api_key_sends_no_authorization_header_at_all builds a keyless client against the stub server over real HTTP and asserts no Authorization header arrives at all — still green, unmodified.

Leak sweep — including the part this diff does not touch

Swept every public-surface object reachable from a client built with a sentinel key and rendered each through repr(), str() and format(): 13 objects, 0 render the key. 5 of those are on the credential-bearing chain this diff touched (Comfy, AsyncComfy, ComfyLow, AsyncComfyLow, _Prepared); the other 8 were not touched (AssetFactory, AsyncAssetFactory, JobFactory, AsyncJobFactory, Models, AsyncModels, Workflow, WorkflowFactory) and were pointed at by the same sweep, which is the half that would otherwise have gone unchecked. The remaining handle reprs (Job, AsyncJob, Asset, Output, AsyncOutput) need a live server to construct, so they were read instead: each renders only ids/status/paths, never its transport. grep -rn 'import logging\|print(' over src/ returns nothing — the SDK does no logging at all, which is how "never logged" holds.

Tests

tests/test_api_key.py is new, and every case runs against both Comfy and AsyncComfy:

• the table — explicit-only, env-only, neither (raises), both-present (explicit wins);
• locality — both httpx send paths are monkeypatched to raise, so any request attempted during construction surfaces as an AssertionError instead of the expected MissingApiKey;
• the message names COMFY_API_KEY, the api_key= argument, and COMFY_BASE_URL; it is a ComfyError with code="missing_api_key" and http_status is None;
• no leak — the key is absent from repr/str of the client, its transport and _Prepared, whichever source it came from; and a keyed client that gets a 401 back raises an error carrying no key;
• normalization — whitespace stripped, blank counts as unset at either source;
• the carve-out — a COMFY_BASE_URL deployment still builds keyless and sends nothing, still picks up COMFY_API_KEY when set, and Cloud named explicitly (trailing slash included) still requires a key;
• end to end — a key resolved from the environment really arrives at the stub server as Bearer ….

tests/conftest.py gains an autouse fixture stripping an ambient COMFY_API_KEY, mirroring the existing COMFY_BASE_URL one: now that the SDK reads that variable, a key exported in a developer's shell would silently authenticate the clients the suite builds deliberately without one, turning the no-credentials-sent assertions green for the wrong reason. Three pre-existing tests that built a keyless client against the Cloud default (two in test_base_url_env.py, one in test_user_agent.py) now pass a key — none of them was about credentials.

Acceptance criteria

Criterion
Explicit argument beats the environment	✅
COMFY_API_KEY read when no explicit key	✅
Clear, named error raised locally, no network call	✅ against Comfy Cloud — see the judgment call above
Error names the environment variable	✅
Key never logged / in repr/str / in an exception message, with a test	✅
Resolution order documented in the package reference	✅ README "Where the key comes from", module docstrings, CHANGELOG
Table-driven test over three cases + both-present	✅

Unexercised artifacts

The source ticket links two internal planning documents (a PRD section and a gameplan row) that specify the resolution order. Both are on an internal collaboration tool this worker cannot reach, so the order implemented here comes from the ticket's own acceptance criteria, not from reading those documents — if they say something more specific about the self-hosted carve-out, that is the thing to check at review. The ticket's parent epic was likewise named but not fetched. No attachment was reachable and no comment on the ticket carried substantive detail.

Provenance

• Authored by: agent-work loop
• Verified: ruff check . clean; ruff format --check . 45 files already formatted; mypy src no issues in 17 files; pytest -q 217 passed / 4 skipped (up from 213 passed pre-change); scripts/check_drift.py models in sync; scripts/check_public_repo_hygiene.py no internal-only references. Live read-only falsification against cloud.comfy.org as quoted above.
• Deviations: the missing-credential error is raised for the Comfy Cloud target only, not unconditionally — an unconditional raise would remove the repo's documented and tested keyless self-hosted surface. Rationale and consequences are in "The one judgment call" above. No other criterion was skipped.

Summary by CodeRabbit

• New Features

  • Added API key resolution from an explicit value or the COMFY_API_KEY environment variable.
  • Added public MissingApiKey and API_KEY_ENV_VAR exports.
  • Custom deployments can operate without credentials; Comfy Cloud requires an API key.
  • Added authentication status indicators and secure client representations that never expose credentials.

• Documentation

  • Documented credential precedence, validation, deployment behavior, and secure credential handling.

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📝 Walkthrough

Walkthrough

The SDK now resolves API keys from explicit arguments or COMFY_API_KEY, validates missing Comfy Cloud credentials during construction, supports keyless custom deployments, exports MissingApiKey and API_KEY_ENV_VAR, and redacts credentials from representations and exceptions.

Changes

Credential resolution and safe authentication state

Layer / File(s)	Summary
Credential contract and client construction src/comfy_sdk/client.py, src/comfy_sdk/exceptions.py, src/comfy_sdk/__init__.py, README.md, CHANGELOG.md	Sync and async clients trim and resolve credentials by precedence. Comfy Cloud raises MissingApiKey when no key is available. Custom deployments can remain unauthenticated. The new constant and exception are publicly exported.
Authentication state and representations src/comfy_sdk/client.py, src/comfy_low/transport.py	Clients and transports expose authentication presence and base URL in safe representations without including API keys.
Credential behavior validation tests/test_api_key.py, tests/conftest.py, tests/test_base_url_env.py, tests/test_user_agent.py	Tests cover credential precedence, normalization, missing-key errors, redaction, keyless deployments, authorization headers, and construction-time environment isolation.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Merge Risk: 🟠 High · up to f6d06

The change can still allow keyless clients for valid Comfy Cloud URLs with an explicit default port, causing a delayed 401 instead of the promised local error, and embedded credentials in base URLs may be exposed through client representations. These correctness and secret-handling risks should be fixed before merging.

Suggested reviewers: wei-hai

Sequence Diagram(s)

sequenceDiagram
  participant Caller
  participant Comfy
  participant _resolve_api_key
  participant ComfyLow
  participant MissingApiKey
  Caller->>Comfy: construct with api_key and base URL
  Comfy->>_resolve_api_key: resolve explicit key or COMFY_API_KEY
  _resolve_api_key->>ComfyLow: pass trimmed key or None
  _resolve_api_key->>MissingApiKey: raise when Comfy Cloud has no key

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[robinjhuang]

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Actionable comments posted: 3

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Inline comments:
In `@src/comfy_low/transport.py`:
- Around line 151-156: Redact URL userinfo before rendering base_url in __repr__
for _Prepared (src/comfy_low/transport.py:151-156), ComfyLow
(src/comfy_low/transport.py:281-284), AsyncComfyLow
(src/comfy_low/transport.py:616-619), Comfy (src/comfy_sdk/client.py:204-207),
and AsyncComfy (src/comfy_sdk/client.py:316-318). Reuse one consistent sanitized
URL value so proxy credentials never appear in representations.

In `@src/comfy_sdk/client.py`:
- Around line 134-141: Update the Comfy Cloud detection around the base_url
comparison to normalize and compare scheme, host, and effective port, treating
an explicit HTTPS default port such as :443 as equivalent to
COMFY_CLOUD_BASE_URL. Preserve the existing MissingApiKey behavior for all
equivalent Comfy Cloud URLs, and add a regression test covering
COMFY_BASE_URL=https://cloud.comfy.org:443/.

In `@tests/test_api_key.py`:
- Around line 69-70: Update the affected client-construction tests in
test_api_key.py to close every Comfy and AsyncComfy instance through the
appropriate with or async with context manager, splitting sync and async
lifecycle cases where necessary while preserving the existing assertions.

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📒 Files selected for processing (10)

• CHANGELOG.md
• README.md
• src/comfy_low/transport.py
• src/comfy_sdk/__init__.py
• src/comfy_sdk/client.py
• src/comfy_sdk/exceptions.py
• tests/conftest.py
• tests/test_api_key.py
• tests/test_base_url_env.py
• tests/test_user_agent.py

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