Access Anthropic Claude Fable 5.2—also searched as Fable 5.2— through EvoLink's unified chat API. Test long-context coding, tool use, prompt caching before integrating.
Anthropic·Text Generation·Available
From $7.600 / 1M input tokens$8.000 official price-5%
Production routeThis rate reflects platform-side availability — only confirmed server errors (HTTP 500 / empty response) count as failures. User-side issues (content moderation, invalid params, cancellation) plus rate limits, timeouts and auth errors are excluded. Before real traffic arrives, empty buckets may display as available.Live
Live
Context
1M context · 128K max output
Best For
The hardest repository-scale coding, longest agent runs, judgment-heavy review
Anthropic’s latest Fable model for demanding reasoning, long-horizon agents, and judgment-heavy review. Five billing dimensions — input, cache write, cache read, output, and the web search tool — are metered separately.
Claude Fable 5.2
Anthropic’s latest Fable model
Selected
Model ID
claude-fable-5-2
Best for
Repository-scale software engineering, long-horizon agent runs with heavy tool use, high-stakes code review, and research or analysis work where a wrong answer costs more than a premium token rate.
Input
$7.600 / 1M-5%
516.8 cr / 1M$8.000official price
Cache write
$9.500 / 1M-5%
646 cr / 1M$10.000official price
Cache read
$0.192 / 1M-4%
13 cr / 1M$0.200official price
Output
$38.000 / 1M-5%
2584 cr / 1M$40.000official price
All rates are per 1M tokens, shown in USD and credits, and reflect your account's current pricing.
Claude Fable 5.2 pricing
Estimate what one Claude Fable 5.2 request costs before you integrate. The calculator uses your account's current rates, with official pricing as a reference.
Request calculator
Enter the token mix for one request and the number of successful tool calls.
Only successful server-side calls are billed per call; failed attempts have no tool fee, but tokens still apply.
Web search$0.010/ call·0.68 cr / call
Claude Fable 5.2 API for the hardest coding and agent work
Call Anthropic’s latest Fable model for demanding reasoning and long-horizon agentic work through EvoLink’s unified API at $7.600 / $38.000 per million input / output tokens. Includes a 1,000,000-token context window, 128K max output, prompt caching with separate write and read rates, and the per-search web search tool.
Claude Fable 5.2 is served on EvoLink under the model ID claude-fable-5-2 through Chat Completions · Anthropic Messages, with the same API key and balance you use for every other model. It offers a 1M context window and up to 128K output tokens, plus long-context coding, tool use, prompt caching.
Claude Fable 5.2 specs and capabilities
Numbers come from the EvoLink route configuration; capabilities are what the API exposes today.
Context window
1M tokens
Max output
128K tokens
Input
Text + images
Output
Text · JSON (structured output) · tool calls
Reasoning
Thinking mode (on by default)
Tool use
Function calling with multi-step tool sequences
Prompt caching
Cache write + cache read rates
Server-side tools
Web search, billed per successful call
Protocols
Chat Completions · Anthropic Messages
Model ID
claude-fable-5-2
Where Claude Fable 5.2 earns its premium rate
Top-tier pricing only pays off when a task is hard enough that a better answer removes work downstream. Route to Fable 5.2 by the cost of being wrong, not by the cost per token.
Repository-scale software engineering
Inspect large codebases, trace dependencies across services, and plan multi-file changes while holding architectural constraints in one context. Measure accepted patches and review time rather than isolated snippet quality.
Long-horizon agents with heavy tool use
Multi-step orchestration, tool selection, and code execution over long runs, where a single wrong branch costs far more than the token difference. Replay complete assistant messages, tool-call IDs, arguments, and tool results across turns.
High-stakes review and analysis
Security review, migration planning, contract and research analysis, and anything where a confident wrong answer is expensive. The 1M-token window keeps the full evidence set in one place.
When another route is the better choice
Everyday coding, high-volume agents, classification, and latency-sensitive chat usually belong on Claude Sonnet 5.5. Compare Claude Opus 5.5’s current token rates and answer quality before choosing it as the default flagship route.
Two ways to use Claude Fable 5.2: EvoLink API or Agent
Use the EvoLink API for product backends and batch jobs, or call Claude Fable 5.2 from Codex, Claude, or Gemini for coding and analysis workflows. Both paths share the same EvoLink API key, balance, model ID, and request history.
Option 1
Integrate with the EvoLink API
Best for: product backends, batch jobs, automated pipelines
Send OpenAI-compatible Chat Completions (or Anthropic Messages) requests to EvoLink and control the model ID, system prompt, output budget, tools, and structured output.
1Create an EvoLink API key in the console
2Point your OpenAI or Anthropic SDK at the EvoLink base URL and select the model ID shown above
3Send one representative request and read the usage field for input, cached, and output tokens
4Set max_tokens and retries per task; keep tool-call IDs and results across turns
Best for: coding, review, and analysis tasks in Codex, Claude, and Gemini
Give the Agent the task, the inputs to include, and the acceptance criteria. It assembles the request, calls Claude Fable 5.2 through EvoLink, and returns the answer with token usage.
1Set EVOLINK_API_KEY in your local environment; never put it in code or a prompt
2Describe the task, the inputs to include, and the expected output format
3Ask the Agent to call Claude Fable 5.2 through EvoLink and show the request before sending
4Let the Agent report the answer, token usage, and any error body
Claude Fable 5.2 API code example and error handling
This example shows the shortest runnable request: an OpenAI-compatible Chat Completions call with a system prompt, a user message, and an output budget. Open the API tab for the complete parameter and response reference.
curl -X POST https://api.evolink.ai/v1/chat/completions \
-H "Authorization: Bearer $EVOLINK_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "claude-fable-5-2",
"messages": [
{ "role": "system", "content": "You are a senior engineer reviewing a pull request." },
{ "role": "user", "content": "Review this diff and list the blocking issues with file and line:\n<diff>" }
],
"max_tokens": 8192
}'
# Anthropic Messages is also available at /v1/messages with the same model
# ID.
# The response includes choices[0].message and a usage object
# (prompt_tokens, completion_tokens, and cache read / write tokens when
# caching applies).
Invalid request or unsupported parameter
Check the model ID, the messages array, and parameter ranges against the API reference; remove fields this route does not support.
Authentication or balance issue
Check the Authorization bearer token and confirm the available balance in the console.
Context length exceeded
Prompt tokens exceed the Claude Fable 5.2 context window. Trim or retrieve only the relevant evidence and reuse cached prefixes.
Rate limited (429)
Back off and retry with jitter; batch or queue requests instead of sending parallel bursts.
Content or tool call rejected
Review sensitive content, malformed tool-call arguments, and JSON schema mismatches before retrying.
Adopt Claude Fable 5.2 without replacing your model stack
Keep one EvoLink client and API key, route the hardest workloads to Fable 5.2, and retain tested alternatives for simpler or latency-sensitive traffic.
01
Use the existing compatible client flow
Point the client at EvoLink, authenticate with the same API key, and select claude-fable-5-2. Both the OpenAI-compatible Chat Completions endpoint and the Anthropic Messages endpoint work.
Low migration
02
Use the documented API model ID
The API route is claude-fable-5-2 on both protocols. The page URL and the model parameter are identical for this model.
ID checked
03
Structure prompts for cache reuse
Put the stable system prompt, repository instructions, and tool schemas at the front of the request so the expensive prefix is written once and read cheaply for the rest of the session.
Cost control
04
Route tasks by completed-task value
Compare success rate, retries, output tokens, cache hits, wall-clock time, and human correction against Claude Opus 5.5 and Claude Fable 5.1 — not token price alone.
Evaluate
Prompt caching billed as two separate dimensions
Storing a prefix costs $9.500 per 1M tokens; reusing it costs $0.192 per 1M tokens. Stable system prompts, repository instructions, and tool schemas pay the write once and then use the separate cache-read rate across the run.
1M-token context with a 128K max output
Keep connected code, specifications, documents, and agent state in one working context. Treat the limit as capacity rather than a target: retrieve relevant evidence, cache the stable prefix, and set task-appropriate output budgets.
Thinking is always on; effort sets its depth
Adaptive thinking cannot be turned off on Fable 5.2, and effort defaults to high. Requests that send thinking disabled or a fixed budget are converted to adaptive thinking on EvoLink instead of failing. max_tokens caps thinking and the answer together, so a low cap can end a response before any text: lower effort or raise max_tokens.
Replay real workloads before shifting production traffic
A lower per-token rate does not guarantee a lower completed-task cost. Model behavior can change billed tokens, retries, and tool paths, so compare success rate, total cost, and human correction on production samples before shifting traffic.
Forced tool choice and thinking history require migration checks
Fable 5.2 rejects forced tool_choice values any and tool. Other Claude models also cannot read Fable 5.2 thinking blocks, and editing earlier turns invalidates those blocks, so keep conversation history append-only and test cross-model fallbacks before production routing.
Five billing dimensions, metered separately
Claude Fable 5.2 does not bill as a single blended rate. Understanding which dimension a workload actually consumes is what makes a top-tier budget predictable.
Input and output tokens
The two dimensions every request touches: $7.600 per 1M input tokens and $38.000 per 1M output tokens on EvoLink, compared with Anthropic’s $8.000 and $40.000. Output dominates on generation-heavy work, so cap max_tokens by task complexity.
Cache write and cache read
Storing a prefix costs $9.500 per 1M tokens; reusing it costs $0.192 per 1M tokens. Stable system prompts, repository instructions, and tool schemas pay the write once and then use the separate cache-read rate across the run.
Web search tool
Billed per search at $0.010. Search results also enter the request as ordinary input tokens, so a research-heavy turn pays both the per-search fee and the tokens it pulls in.
Compare Claude routes after workload testing
EvoLink
First verify whether Fable 5.2 reduces retries and review effort on your own tasks. Then compare price, context, caching, and workload fit to choose the production route.
Repository-scale software engineering, long-horizon agent runs with heavy tool use, high-stakes code review, and research or analysis work where a wrong answer costs more than a premium token rate.
The previous Fable generation; compare its token and cache-read rates for your workload.
Compare Claude Opus 5.5’s current token rates and answer quality before choosing it as the default flagship route.
Claude Fable 5.2
Input / output$7.6 / $38
Context1M
CachingRead + write
Best forRepository-scale software engineering, long-horizon agent runs with heavy tool use, high-stakes code review, and research or analysis work where a wrong answer costs more than a premium token rate.
Is the Claude Fable 5.2 API available through EvoLink?
Yes. Claude Fable 5.2 is available on EvoLink as a production route under model ID "claude-fable-5-2".
What is the Claude Fable 5.2 API model ID?
Send model "claude-fable-5-2". The same ID works for both the OpenAI-compatible Chat Completions endpoint and the Anthropic Messages endpoint. Claude Mythos 5.2 is a separate model that Anthropic limits to verified organizations; it is not offered here.
How much does the Claude Fable 5.2 API cost on EvoLink?
EvoLink pricing: $7.600 per 1M input tokens and $38.000 per 1M output tokens, against Anthropic’s $8.000 and $40.000.
How is Claude Fable 5.2 prompt caching billed?
Cache write and cache read are separate dimensions: $9.500 per 1M cache write tokens and about $0.192 per 1M cache read tokens on EvoLink, versus $10.000 and $0.200 official.
How is the Claude Fable 5.2 web search tool billed?
Web search is charged per search at $0.010. Tokens the search results add to the request are billed normally.
Can I call Claude Fable 5.2 with an OpenAI-compatible API?
Yes. Send model "claude-fable-5-2" to EvoLink’s OpenAI-compatible Chat Completions endpoint, or use the Anthropic Messages endpoint with the same API key. Claude Code and other Anthropic-native clients work by pointing the base URL at EvoLink.
What context window and max output does Claude Fable 5.2 support?
The EvoLink route records a 1,000,000-token context window with up to 128K output tokens per response.
Can I turn off thinking on Claude Fable 5.2?
No. Adaptive thinking is always on, with high as the default effort. Lower effort to reduce reasoning depth, latency, and token use. On EvoLink, a request that sends thinking disabled or a fixed budget is converted to adaptive thinking instead of returning an error.
What workloads are a good fit for Claude Fable 5.2?
Claude Fable 5.2 fits especially demanding coding, long-running agents with heavy tool use, and critical reviews where errors create high downstream costs.
Does Claude Fable 5.2 support forced tool choice?
No. Requests using tool_choice any or tool return HTTP 400. Use auto or none and test tool routing before migration.
What changes when routing a Fable 5.2 conversation to another model?
Only Claude Fable 5.2 and Claude Mythos 5.2 can read Fable 5.2 thinking blocks. Other models drop them, so the turn continues without that reasoning. Keep conversation history append-only as well, because editing earlier turns invalidates those thinking blocks.
How does Claude Fable 5.2 differ from Claude Fable 5.1?
Claude Fable 5.2 succeeds Fable 5.1 at a lower official list price: $8.000 per 1M input tokens and $40.000 per 1M output tokens, with the same 1M-token context window and 128K max output. Most requests only need the new model ID. Re-test long conversations that send thinking blocks back, because editing earlier turns invalidates those blocks.
Claude Fable 5.2 vs Claude Opus 5.5: which should I use?
Start with Claude Opus 5.5 for most coding and agent work: Anthropic lists Fable 5.2 at twice Opus 5.5’s input and output rates. Move a workload to Fable 5.2 when Opus 5.5 at higher effort still falls short, and compare completed-task cost rather than the per-token rate.
Does Claude Fable 5.2 support fast mode on EvoLink?
Not at this time. EvoLink serves Claude Fable 5.2 at standard speed and standard rates; a request that sets speed to fast still runs at standard speed and is not billed at a premium.
