middleware

Jul 13, 2026

Changes in this version

+ var ErrRateLimitExceeded = errors.New("model rate limit exceeded")

+ var ErrTokenBudgetExceeded = errors.New("model token budget exceeded")

+ func ApproximateTokenCount(text string) int64

+ func ContextWithTokenBudget(ctx context.Context, budget *TokenBudget) context.Context

+ func Wrap(base models.Agent, policies ...Middleware) (models.Agent, error)

+ type Middleware interface

+ Wrap func(models.Agent) (models.Agent, error)

+ type MiddlewareFunc func(models.Agent) (models.Agent, error)

+ func (f MiddlewareFunc) Wrap(next models.Agent) (models.Agent, error)

+ type RateLimitMode uint8

+ const RateLimitReject

+ const RateLimitWait

+ type RateLimitPolicy struct

+ Burst int

+ Mode RateLimitMode

+ Per time.Duration

+ Requests int

+ func (p RateLimitPolicy) Wrap(next models.Agent) (models.Agent, error)

+ type RetryPolicy struct

+ DisableJitter bool

+ InitialBackoff time.Duration

+ Jitter float64

+ MaxAttempts int

+ MaxBackoff time.Duration

+ Multiplier float64

+ ShouldRetry func(context.Context, error) bool

+ func (p RetryPolicy) Wrap(next models.Agent) (models.Agent, error)

+ type TimeoutPolicy struct

+ Duration time.Duration

+ func (p TimeoutPolicy) Wrap(next models.Agent) (models.Agent, error)

+ type TokenBudget struct

+ func NewTokenBudget(max int64, estimator TokenEstimator) (*TokenBudget, error)

+ func TokenBudgetFromContext(ctx context.Context) (*TokenBudget, bool)

+ func (b *TokenBudget) Max() int64

+ func (b *TokenBudget) Remaining() int64

+ func (b *TokenBudget) Reset()

+ func (b *TokenBudget) Used() int64

+ type TokenBudgetError struct

+ Max int64

+ Phase string

+ Requested int64

+ Used int64

+ func (e *TokenBudgetError) Error() string

+ func (e *TokenBudgetError) Unwrap() error

+ type TokenBudgetPolicy struct

+ Budget *TokenBudget

+ func (p TokenBudgetPolicy) Wrap(next models.Agent) (models.Agent, error)

+ type TokenEstimator func(string) int64