feat(config, tui): Configurable path suffix for OpenAI-compat endpoints (#2089)

[hongqitai]

Summary

Closes #2089, Closes #1874
Add path_suffix into config, set it to change version:

• like "/v2" to change vertion
• empty str for api which accept only "/chat/completions"
• none is current behavior(add "/v1" to url)

Testing

• [ x ] cargo fmt --all -- --check
• [ x ] cargo clippy --workspace --all-targets --all-features
• [ x ] cargo test --workspace --all-features

Checklist

• [ x ] Updated docs or comments as needed
• [ x ] Added or updated tests where relevant
• [ x ] Verified TUI behavior manually if UI changes

Greptile Summary

This PR adds a configurable path_suffix field to all OpenAI-compatible provider configs, letting users override or suppress the automatically-appended /v1 version segment in API base URLs. The feature is surfaced via TOML config, environment variables (one generic DEEPSEEK_PATH_SUFFIX / CODEWHALE_PATH_SUFFIX that routes by active provider, plus per-provider vars like OPENAI_PATH_SUFFIX), and a new --path-suffix CLI flag.

• versioned_base_url and api_url are refactored to accept an Option<&str> path suffix; a normalize_version helper strips leading slashes so both "v2" and "/v2" are equivalent.
• ARCEE_PATH_SUFFIX is implemented in the config crate and wired up in path_suffix_for, but is absent from the docs/CONFIGURATION.md env-var listing, leaving Arcee users with no documentation for the feature.

Confidence Score: 4/5

Safe to merge with minor documentation fixes; the core URL-building logic is well-tested and the config plumbing is mechanically sound across all providers.

The functional changes are thoroughly tested with unit tests covering empty suffix, non-empty suffix, with and without leading slash, and interaction with beta/versioned base URLs. Documentation has two gaps: missing ARCEE_PATH_SUFFIX entry and unclear description of path_suffix='' stripping behavior.

docs/CONFIGURATION.md needs ARCEE_PATH_SUFFIX added to the per-provider listing and a clearer description of the path_suffix='' stripping behaviour.

Important Files Changed

Filename	Overview
crates/tui/src/client.rs	Core URL-building logic refactored: versioned_base_url and api_url now accept Option<&str> path_suffix; a normalize_version helper strips leading slashes. All call sites updated and well-tested.
crates/config/src/lib.rs	Adds path_suffix to all config structs with correct get/set/unset/list coverage for all providers. ARCEE_PATH_SUFFIX is wired up but missing from docs.
crates/tui/src/config.rs	Adds path_suffix to Config and ProviderConfig; new path_suffix() method and env-var routing are consistent with existing patterns.
crates/tui/src/main.rs	DoctorApiTarget and diagnostic output updated; merge_config and merge_provider_config correctly propagate path_suffix.
crates/cli/src/lib.rs	Adds --path-suffix CLI flag, correctly routed via DEEPSEEK_PATH_SUFFIX env var to all providers.
docs/CONFIGURATION.md	Documents path_suffix broadly but omits ARCEE_PATH_SUFFIX and understates the stripping behavior of path_suffix = "".
crates/tui/src/client/chat.rs	Both chat completion call sites updated to pass self.path_suffix.as_deref(). Straightforward change.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[User config / env var / CLI --path-suffix] --> B{Priority resolution}
    B --> |1st| C[CLI path_suffix flag]
    B --> |2nd| D[Provider-specific env var]
    B --> |3rd| E[Generic CODEWHALE_PATH_SUFFIX]
    B --> |4th| F[Provider config file]
    B --> |5th| G[Root deepseek config]
    C & D & E & F & G --> H[Resolved path_suffix]
    H --> I{api_url called}
    I --> |beta/ path| J[unversioned_base_url + path]
    I --> |other paths| K[normalize_version]
    K --> L{versioned_base_url}
    L --> |Some version| M[unversioned + / + version]
    L --> |None + /beta| N[unversioned + /v1]
    L --> |None + versioned| O[base_url as-is]
    L --> |None + bare| P[base_url + /v1]
    M & N & O & P --> Q[final URL]

Loading

_{Reviews (5): Last reviewed commit: "Merge branch 'main' into feature/path-su..." | Re-trigger Greptile}

[Hmbown]

Thanks @hongqitai. I reviewed this during the v0.8.50 triage pass. This is a useful direction for #2089, but I am not harvesting it into #2504 yet because the current patch is broader than the release slice and has a couple of correctness gaps.

Concrete blockers to address:

• Normalize path_suffix before building URLs. Right now versioned_base_url(base_url, path_suffix.unwrap_or("/v1")) appends the suffix directly, so a config/env/CLI value like v2 or openai/v2 would produce https://hostv2/... instead of https://host/v2/....
• Add config round-trip tests for get_value, set_value, unset_value, and list_values on at least providers.openai.path_suffix, including the explicit empty-string case.
• Add docs/config examples. This adds new CLI flags, env vars for every provider, root DeepSeek compatibility behavior, and provider-table behavior, but the user-facing contract is not described yet.
• Narrow or justify the surface area. Configurable path suffix for OpenAI-compat endpoints (closes #1874) #2089 is about OpenAI-compatible path suffixes; adding env vars and config keys for every provider may be right eventually, but for v0.8.50 it is more risk than I want to harvest without stronger tests.
• Keep this as Refs #2089 until the above is covered end to end; it should not auto-close Configurable path suffix for OpenAI-compat endpoints (closes #1874) #2089 yet.

Once those are fixed, this could become the stronger follow-up compared with the smaller draft in #2506.

[gemini-code-assist]

Code Review

This pull request introduces a new path_suffix configuration option across CLI arguments, TOML configuration files, environment variables, and the TUI client, allowing users to customize or override the default /v1 API version suffix appended to base URLs. Feedback on the changes highlights a bug where the custom path_suffix is ignored if the base URL already contains a version suffix (e.g., /v1 or /v4). To resolve this, it is recommended to strip any existing version suffix from the base URL when a custom path_suffix is explicitly provided, and to update the corresponding test assertions to verify this behavior.

[gemini-code-assist]

Warning

You have reached your daily quota limit. Please wait up to 24 hours and I will start processing your requests again!

[hongqitai]

Fix all pronlems, and add suport for new changes

[Hmbown]

Thanks @hongqitai for the update. I see the branch is now green, which is a good sign. I am keeping it out of the v0.8.52 release freeze because configurable OpenAI-compatible path suffixes are a broad provider/config/docs feature rather than a cleanup fix for the 0.8.51 fallout. This should get a focused review after 0.8.52 is published so we do not bury your work inside the emergency release lane.