Model shortlist

Best agent model APIs for tool-calling workflows

Compare model APIs for agents that need tools, JSON mode, long context, and a budget you can live with.

What is this shortlist for?: Agent models

Agent runs spit out a lot of tokens and burn money when tool loops go wrong. Before you wire one up, check tool calling, JSON reliability, context length, latency, and output price. Then set a budget so a bad loop cannot empty the account overnight.

Source basis: NextModel capability mapping and supported-parameter metadata when available. · Updated 2026-07-01

How to use this shortlist

How to use this shortlist (Agent models)

  1. Match the shortlist to the job. Check whether the Agent models candidates fit your real workload, not only the posted rate.
  2. Run the same prompts. Test two or three candidates on production-like prompts and note quality and output length.
  3. Estimate monthly cost. Use the pricing page or cost calculator with expected token volume.
  4. Set fallback and budget. Pick a primary model, a fallback, and a project budget before production traffic.

Fit score

Recommended candidates agent models

Start with the shortlist, then test real prompts and compare monthly cost before production routing in Canada.

GoogleCatalogHealthytypical

‌Gemini 4 Argon via NextModel: 1M-token context; $2 / 1M tokens in / $10 / 1M tokens out per 1M tokens. Capabilities: streaming, tool, json.

$2 / 1M tokensInput$10 / 1M tokensOutput1MContext
Best forimage understanding, multimodal chat
StreamingTool callingJSON modeVisionLong context
Platform curatedCurated and maintained in the NextModel catalog
View details
AnthropicCatalogHealthyfast

Claude Haiku 5.5 via NextModel: 1M-token context; Starting at $0.1 / 1M tokens in / $0.5 / 1M tokens out per 1M tokens. Capabilities: streaming, tool, json.

Starting at $0.1 / 1M tokensInput$0.5 / 1M tokensOutput1MContext
Best forimage understanding, multimodal chat
StreamingTool callingJSON modeVisionLong context
Platform curatedCurated and maintained in the NextModel catalog
View details
AnthropicCatalogHealthyfast

Claude Sonnet 5.5 via NextModel: 1M-token context; $2 / 1M tokens in / $10 / 1M tokens out per 1M tokens. Capabilities: streaming, tool, json.

$2 / 1M tokensInput$10 / 1M tokensOutput1MContext
Best forimage understanding, multimodal chat
StreamingTool callingJSON modeVisionLong context
Platform curatedCurated and maintained in the NextModel catalog
View details
OpenAICatalogHealthytypical

GPT‑6 Luna via NextModel: 1M-token context; Starting at $0.1 / 1M tokens in / $0.5 / 1M tokens out per 1M tokens. Capabilities: streaming, tool, json.

Starting at $0.1 / 1M tokensInput$0.5 / 1M tokensOutput1MContext
Best forimage understanding, multimodal chat
StreamingTool callingJSON modeVisionLong context
Platform curatedCurated and maintained in the NextModel catalog
View details

Comparison table

Compare the shortlist by price, provider, context, capability, and source.

Use this view when narrowing a production shortlist, building a fallback policy, or comparing model economics for Canada-based teams.

ModelProviderInputOutputContextCapabilitiesBest forLatencyStatusSource
‌Gemini 4 Argongoogle/gemini-4-argonGoogle$2 / 1M tokens$10 / 1M tokens1M
StreamingTool callingJSON modeVision
image understanding, multimodal chat2974-10589msCatalogPlatform curated
Claude Haiku 5.5anthropic/claude-haiku-5.5AnthropicStarting at $0.1 / 1M tokens$0.5 / 1M tokens1M
StreamingTool callingJSON modeVision
image understanding, multimodal chat1321-2017msCatalogPlatform curated
Claude Sonnet 5.5anthropic/claude-sonnet-5.5Anthropic$2 / 1M tokens$10 / 1M tokens1M
StreamingTool callingJSON modeVision
image understanding, multimodal chat1230-2392msCatalogPlatform curated
GPT‑6 Lunaopenai/gpt-6-lunaOpenAIStarting at $0.1 / 1M tokens$0.5 / 1M tokens1M
StreamingTool callingJSON modeVision
image understanding, multimodal chat1722-2681msCatalogPlatform curated
GPT‑6 Solopenai/gpt-6-solOpenAIStarting at $2 / 1M tokens$10 / 1M tokens1M
StreamingTool callingJSON modeVision
image understanding, multimodal chat1752-3715msCatalogPlatform curated
Claude Opus 5.5anthropic/claude-opus-5.5Anthropic$4 / 1M tokens$20 / 1M tokens1M
StreamingTool callingJSON modeVision
image understanding, multimodal chat1845-5119msCatalogPlatform curated
GPT-6 Astraopenai/gpt-6-astraOpenAIStarting at $10 / 1M tokens$50 / 1M tokens1.1M
StreamingTool callingJSON modeVision
image understanding, multimodal chat2408-7945msCatalogPlatform curated
Claude Fable 5.1anthropic/claude-fable-5.1Anthropic$10 / 1M tokens$50 / 1M tokens1M
StreamingTool callingJSON modeVision
image understanding, multimodal chat3187-5152msCatalogPlatform curated

FAQ

Agent models FAQ

Which capabilities matter most for agent models?

Tool calling, structured JSON, enough context for the task, and instructions that stick. Everything else is secondary.

Why do agent workflows get expensive so fast?

They generate long traces: planning text, tool results stuffed back into context, and retries. Cap steps and log token use per run.

Should agents always use the strongest model?

No. Route planning or simple tool picks to cheaper models when quality allows, and reserve stronger models for hard steps.

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