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Answer: Ollama's docs say tasks like agents and coding tools need a context length of at least 64000 tokens. A larger context length increases the memory required, so check VRAM first.

Context length

Context length is the maximum number of tokens the model has access to in memory. The context-length page lists defaults by VRAM:

• under 24 GiB: 4k context;
• 24-48 GiB: 32k context;
• 48 GiB or more: 256k context.

The FAQ still says the default context window size is 4096 tokens, overridable with OLLAMA_CONTEXT_LENGTH. A larger context length increases the memory required to run a model. For best performance, avoid offloading the model to CPU and verify the split under PROCESSOR with ollama ps.

Keep-alive

• Models are kept in memory for 5 minutes before being unloaded by default.
• keep_alive on /api/generate and /api/chat sets how long a model stays loaded; a negative number keeps it loaded, 0 unloads immediately.
• OLLAMA_KEEP_ALIVE changes the time all models are loaded into memory; the keep_alive API parameter overrides the OLLAMA_KEEP_ALIVE setting.
• ollama stop unloads a model immediately.

See also

• ao-idlehw
• ao-context-longbench-v2

Claims

• id: C1 claim: Agent tasks need at least 64000 tokens of context. source: S1 evidence: "agents, and coding tools should be set to at least 64000 tokens."

• id: C2 claim: Larger context needs more memory. source: S1 evidence: "will increase the amount of memory required to run a model."

• id: C3 claim: Models stay loaded 5 minutes by default. source: S2 evidence: "By default models are kept in memory for 5 minutes before being unloaded."

• id: C4 claim: keep_alive overrides OLLAMA_KEEP_ALIVE. source: S2 evidence: "endpoints will override the OLLAMA_KEEP_ALIVE setting."

Sources

• [S1] Context length. Ollama docs (GitHub). https://github.com/ollama/ollama/blob/main/docs/context-length.mdx . License: MIT (ollama/ollama LICENSE). Accessed 2026-11-09.

• [S2] Ollama FAQ. Ollama docs (GitHub). https://github.com/ollama/ollama/blob/main/docs/faq.mdx . License: MIT (ollama/ollama LICENSE). Accessed 2026-11-09.

License: this note is CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Summary by iinventedlight (AI-assisted). Sources: GitHub repository docs under Apache License 2.0 (https://www.apache.org/licenses/LICENSE-2.0) or MIT License (https://opensource.org/licenses/MIT), as listed per source; copyright notices remain with the original authors. Text was condensed and changed from the originals.

@misc{iil_note_sh9ew70m,
  author = {{iinventedlight}},
  title = {{Sizing Ollama for agent work: context length and keep-alive}},
  howpublished = {iinventedlight Library},
  year = {2026},
  date = {2026-11-09},
  url = {https://iinventedlight.com/library/notes/ao-idlehw-ollama-context-and-keepalive/},
  note = {Permanent ID iil:note:sh9ew70m. License: CC-BY-4.0.},
}

Markdown

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