Repository navigation
[FEATURE]: Allow overriding model input limits for OpenAI long-context models #16298
Description
Feature hasn't been suggested before.
- I have verified this feature I'm about to request hasn't been suggested before.
Describe the enhancement you want to request
I would like opencode to support user-overridable input limits for OpenAI models such as gpt-5.4, or otherwise align its effective limits more closely with the official OpenAI model documentation.
Background
OpenAI documents gpt-5.4 as having a 1,050,000 token context window and 128,000 max output tokens.
In opencode, openai:gpt-5.4 currently appears to be loaded with:
context: 1,050,000input: 272,000output: 128,000
Because opencode's compaction logic prefersmodel.limit.inputwhen it is present, long conversations may be compacted much earlier than users would expect from the official GPT-5.4 context window.
Requested enhancement
Please consider one of the following:
- Allow
provider.models.<model>.limit.inputto be overridden in user config, and make sure that override is respected at runtime. - Add an explicit advanced setting to opt into the full documented long-context budget for supported models/providers.
- Revisit the metadata source used for OpenAI GPT-5.x models so opencode does not enforce a much smaller effective input budget unless there is a confirmed upstream reason.
Why this would help
- It would let advanced users fully use the long-context models they are already paying for.
- It would reduce unnecessary early compaction and summarization.
- It would make model behavior more predictable and closer to official provider documentation.
- It would improve parity with OpenAI's own tooling, where client-side context budget is configurable.
Additional note
This request is not asking opencode to bypass any upstream provider limits. It is only asking for either: - more accurate defaults, or
- a user-visible override for the client-side/model-metadata limit that opencode uses for compaction decisions.
If the current272,000input limit is intentional because of a known upstream constraint, documenting that clearly would also be very helpful.
Reacted by Tarek Haoula, Raymel, Brendan Duke, Sergey Kostrukov, vyls and Jun Guo
Activity
github-actions commentedon Mar 6, 2026
This issue might be a duplicate of existing issues. Please check:
Please review these issues to see if your request is already covered or can be addressed as part of an existing discussion.
ykswang commentedon Mar 6, 2026
I originally opened this as a feature request, but after tracing the implementation this looks more like a bug in the existing model override behavior.
Specifically,
provider.models.<model>.limit.inputis currently ignored in two places:limitoverrides such as:{ "provider": { "anthropic": { "models": { "claude-sonnet-4-20250514": { "limit": { "input": 123456 } } } } } }This means model-level input limit overrides are ineffective even though model overrides already exist for other fields.
I'm preparing a small fix that: