Ollama

The Ollama provider uses provider key ollama and the HPD-Agent.Providers.Ollama package. It does not require an API key. ModelName is a local Ollama model tag, such as llama3.2 or llama3:8b.

Start Ollama and make sure the model is available locally:

ollama pull llama3.2

Use fluent setup:

using HPD.Agent;
using HPD.Agent.Providers.Ollama;

var agent = await new AgentBuilder()
    .WithOllama(model: "llama3.2")
    .BuildAsync();

var result = await agent.RunAsync("Write one sentence about local model setup.");
Console.WriteLine(result.Text);

Provider configuration stay small. Configure the Ollama server connection on the provider, and put model behavior on the agent's Clients.Chat default or a run's complete Clients.Chat replacement:

using HPD.Agent;
using HPD.Agent.Providers.Ollama;

var agent = await new AgentBuilder()
    .WithOllama(
        model: "qwen3:latest",
        endpoint: "http://localhost:11434",
        configure: ollama =>
        {
            ollama.TimeoutMs = 120_000;
        })

    .WithOllamaChatRequestOptions(ollama =>
    {
        ollama.KeepAlive = "10m";
        ollama.NumCtx = 8192;
        ollama.NumGpu = 99;
        ollama.UseMlock = true;
    })
    .BuildAsync();

The provider helper writes the same portable fields, typed providerConfig, and typed providerOptions into Clients.Chat. Use the runtime selection guide for the canonical JSON and YAML shape.

Endpoint resolution in fluent setup checks:

1. the explicit endpoint argument
2. OLLAMA_ENDPOINT
3. OLLAMA_HOST
4. http://localhost:11434

Runtime Options

Use Clients.Chat or AgentRunConfig.Clients.Chat for generic model behavior:

• ModelId
• Temperature
• TopP
• TopK
• MaxOutputTokens
• FrequencyPenalty
• PresencePenalty
• Seed
• StopSequences
• ResponseFormat
• Reasoning

Use OllamaChatRequestOptions for Ollama-only request properties:

Option	Ollama key	Meaning
KeepAlive	keep_alive	How long Ollama keeps the model loaded after the request, such as 10m, 1h, or -1.
Template	template	Prompt template override for this request. This overrides the template defined in the model file.
NumCtx	num_ctx	Context window size used by the model.
NumGqa	num_gqa	Grouped-query-attention group count required by some model architectures.
NumGpu	num_gpu	Number of layers to offload to GPU.
MainGpu	main_gpu	Main GPU index for small tensors when multiple GPUs are available.
NumBatch	num_batch	Maximum batch size for prompt processing.
NumThread	num_thread	Number of CPU threads used for generation. Ollama auto-detects when unset.
NumKeep	num_keep	Number of tokens to keep from the initial prompt. Ollama supports -1 to keep all.
MiroStat	mirostat	Enables Mirostat sampling: 0 disabled, 1 Mirostat, 2 Mirostat 2.0.
MiroStatEta	mirostat_eta	Mirostat learning rate. Higher values react more quickly to feedback.
MiroStatTau	mirostat_tau	Mirostat target entropy. Lower values are more focused; higher values add variety.
RepeatLastN	repeat_last_n	Number of prior tokens considered for repetition penalties. Ollama supports 0 to disable and -1 for the full context.
RepeatPenalty	repeat_penalty	Repetition penalty strength. Higher values penalize repetition more strongly.
MinP	min_p	Minimum probability threshold relative to the most likely token.
TypicalP	typical_p	Locally typical sampling value. Lower values make output more conservative.
TfsZ	tfs_z	Tail-free sampling value. A value near 1 disables the setting.
PenalizeNewline	penalize_newline	Whether newline tokens are penalized during repetition control.
UseMmap	use_mmap	Whether model weights are memory-mapped.
UseMlock	use_mlock	Whether to lock model memory to avoid swapping.
LowVram	low_vram	Enables low-VRAM mode.
F16kv	f16_kv	Enables f16 key/value cache.
LogitsAll	logits_all	Returns logits for all tokens, not only the last token.
VocabOnly	vocab_only	Loads only the vocabulary, not model weights.
Numa	numa	Enables NUMA support.

Sampling values that already exist on ChatClientConfig, such as Temperature, TopP, TopK, MaxOutputTokens, Seed, FrequencyPenalty, PresencePenalty, and StopSequences, stay on Clients.Chat or AgentRunConfig.Clients.Chat.

Caveats

Validation checks endpoint URI shape. A successful build still requires a reachable Ollama server and a pulled model.

OLLAMA_ENDPOINT and OLLAMA_HOST are used by fluent .WithOllama(...). JSON/config setup should include Endpoint when the server is not at http://localhost:11434.