Files
ModelRouter/internal/lua/adapters/anthropic.lua
JianFeeeee 131a42a169 fix(adapters): sanitize tool-call ids so one bad upstream can't kill every Claude slot
Anthropic requires tool_use.id / tool_result.tool_use_id to match
^[a-zA-Z0-9_-]{1,64}$ and rejects the WHOLE request otherwise with
REQUEST_BODY_INVALID / "Invalid tool use format". OpenAI has no such rule, so
an OpenAI-compatible model can mint an id like "bash:0"
(xinjianya/moonshotai/kimi-k3 does exactly that).

In a fan-out router that id does not stay local: the client stores it in its
history and replays it to every other source. One such id therefore kills
every Claude slot at once — justwoker, tabitoken and 扇贝 are all
Claude-behind-{OpenAI,Anthropic} — and an AUTO request falls through all four
tiers to whatever tolerant model is left. Observed live: 4 consecutive 503
"all N auto providers failed" with tier 1/2/3 each reporting the same 400.

Both directions are sanitized, in both adapters:
  - request:  tool_calls[].id and tool_call_id, so poisoned history recovers
  - response: non-streaming tool_calls[].id and the first streamed fragment,
              so a bad id never enters a client session in the first place

safe_tool_id is pure and deterministic, so a call and its result are rewritten
identically within one request. A rewritten id keeps an 8-hex digest of the
original, without which distinct ids could collapse ("a:b" and "a_b") into a
duplicate/unpaired tool_use. Already-legal ids pass through byte-identical, so
well-behaved traffic is unaffected. openai.lua carries its own copy because
Lua adapters have no shared prelude.

Streamed argument fragments carry no id and must stay id-less, otherwise
index-based accumulation on the client breaks; a test pins that.
2026-09-05 22:18:31 +08:00

429 lines
17 KiB
Lua

local adapter = {}
adapter.name = "anthropic"
adapter.version = "3.0.0"
adapter.endpoint = "/v1/messages"
adapter.headers = {
["anthropic-version"] = "2023-06-01",
}
-- ============================================================
-- helpers
-- ============================================================
local ROLE_WHITELIST = {
system = true, user = true, assistant = true, tool = true,
}
-- Anthropic requires tool_use.id / tool_result.tool_use_id to match
-- ^[a-zA-Z0-9_-]{1,64}$ and rejects the WHOLE request otherwise with
-- REQUEST_BODY_INVALID / "Invalid tool use format". OpenAI imposes no such
-- rule, so an OpenAI-compatible upstream can hand a client an id like
-- "bash:0" (observed from moonshotai/kimi-k3); once that lands in the
-- client's history, every later replay kills every Claude slot at once and
-- an AUTO chain falls through all tiers.
--
-- safe_tool_id is pure and deterministic, so a tool_use block and its
-- matching tool_result are rewritten identically within one request. A
-- rewritten id keeps an 8-hex digest of the ORIGINAL id: without it two
-- distinct ids could collapse into one ("a:b" and "a_b"), which Anthropic
-- rejects as a duplicate/unpaired tool_use. Already-legal ids pass through
-- untouched so upstreams that round-trip their own ids are unaffected.
local TOOL_ID_MAX = 64
local function safe_tool_id(id)
if type(id) ~= "string" or id == "" then return "" end
local clean = string.gsub(id, "[^A-Za-z0-9_-]", "_")
if clean == id and #clean <= TOOL_ID_MAX then
return clean
end
local digest = string.sub(sha256_hex(id), 1, 8)
local keep = TOOL_ID_MAX - #digest - 1
if #clean > keep then clean = string.sub(clean, 1, keep) end
return clean .. "_" .. digest
end
local function collect_blocks(content)
if type(content) == "string" then
if content == "" then return {} end
return { { type = "text", text = content } }
end
if type(content) ~= "table" then return {} end
local blocks = {}
for _, p in ipairs(content) do
if type(p) == "string" then
table.insert(blocks, { type = "text", text = p })
elseif type(p) == "table" then
if p.type == "text" then
table.insert(blocks, { type = "text", text = p.text or "" })
elseif p.type == "image_url" and type(p.image_url) == "table" and p.image_url.url then
local url = p.image_url.url
local mt, b64 = string.match(url, "^data:([^,]+);base64,(.+)$")
if b64 then
table.insert(blocks, { type = "image", source = { type = "base64", media_type = mt or "image/png", data = b64 } })
else
table.insert(blocks, { type = "image", source = { type = "url", url = url } })
end
else
-- Unknown content type: preserve for forward compatibility
table.insert(blocks, p)
end
end
end
return blocks
end
local function text_of(content)
if type(content) == "string" then return content end
local t = ""
for _, p in ipairs(content or {}) do
if type(p) == "string" then
t = t .. p
elseif type(p) == "table" and p.type == "text" and p.text then
t = t .. p.text
end
end
return t
end
--- Append blocks to the last user message (merge) or create a new one.
local function append_user(msgs, blocks)
if #msgs > 0 and msgs[#msgs].role == "user" then
for _, b in ipairs(blocks) do
table.insert(msgs[#msgs].content, b)
end
else
table.insert(msgs, { role = "user", content = blocks })
end
end
-- ============================================================
-- transform_request (OpenAI → Anthropic)
-- ============================================================
function adapter.transform_request(raw_body)
local ok, req = pcall(json.decode, raw_body)
if not ok or type(req) ~= "table" then return raw_body end
local msgs = {}
local system = ""
local pending_tool = {} -- accumulated tool_result blocks
for _, m in ipairs(req.messages or {}) do
local role = m.role or "user"
if role == "system" then
system = system .. text_of(m.content) .. "\n"
elseif role == "assistant" then
-- Build content array: text/image blocks from content + tool_use from tool_calls
local blocks = collect_blocks(m.content)
if type(m.tool_calls) == "table" then
for _, tc in ipairs(m.tool_calls) do
if type(tc) == "table" then
local fn = tc["function"] or {}
local args = fn.arguments
local input = {}
if type(args) == "string" and args ~= "" then
local ok2, parsed = pcall(json.decode, args)
if ok2 and type(parsed) == "table" then input = parsed end
elseif type(args) == "table" then
input = args
end
table.insert(blocks, {
type = "tool_use",
id = safe_tool_id(tc.id),
name = fn.name or "",
input = input,
})
end
end
end
table.insert(msgs, { role = "assistant", content = blocks })
elseif role == "tool" then
-- Accumulate consecutive tool results; will be flushed as one
-- user message with tool_result content blocks.
table.insert(pending_tool, {
type = "tool_result",
tool_use_id = safe_tool_id(m.tool_call_id),
content = text_of(m.content),
})
else
-- user / any other role: flush pending tool results first
if #pending_tool > 0 then
append_user(msgs, pending_tool)
pending_tool = {}
end
append_user(msgs, collect_blocks(m.content))
end
end
-- Flush any trailing tool results
if #pending_tool > 0 then
append_user(msgs, pending_tool)
end
-- ── Build Anthropic request ──────────────────────────────
local anthropic_req = {
model = req.model or "claude-sonnet-4-20250514",
max_tokens = req.max_tokens or 4096,
messages = msgs,
stream = req.stream or false,
}
-- ── tools ────────────────────────────────────────────────
local has_tools = false
if req.tools and type(req.tools) == "table" then
local tools = {}
for _, t in ipairs(req.tools) do
if type(t) == "table" and t.type == "function"
and type(t["function"]) == "table" then
local fn = t["function"]
table.insert(tools, {
name = fn.name or "",
description = fn.description or "",
input_schema = fn.parameters or { type = "object", properties = {} },
})
end
end
if #tools > 0 then
anthropic_req.tools = tools
has_tools = true
end
end
-- ── tool_choice ──────────────────────────────────────────
-- OpenAI → Anthropic mapping:
-- "auto" → {type:"auto"}
-- "none" → remove tools entirely (Anthropic has no "none")
-- "required" → {type:"any"}
-- {type:"function", function:{name:"X"}} → {type:"tool", name:"X"}
if has_tools and req.tool_choice then
local tc = req.tool_choice
if type(tc) == "string" then
if tc == "auto" then
anthropic_req.tool_choice = { type = "auto" }
elseif tc == "none" then
anthropic_req.tools = nil
anthropic_req.tool_choice = nil
elseif tc == "required" then
anthropic_req.tool_choice = { type = "any" }
end
elseif type(tc) == "table" and tc.type == "function" then
local fn = tc["function"] or {}
anthropic_req.tool_choice = { type = "tool", name = fn.name or "" }
end
end
-- ── thinking (opt-in via extra_body) ──────────────────────
-- Default: OFF. Client sends extra_body.thinking to enable.
-- Example: {"extra_body": {"thinking": {"type": "enabled", "budget_tokens": 4096}}}
if type(req.extra_body) == "table" and type(req.extra_body.thinking) == "table" then
anthropic_req.thinking = req.extra_body.thinking
end
-- ── system ───────────────────────────────────────────────
if system ~= "" then
-- Strip trailing newline from accumulation
anthropic_req.system = string.match(system, "^(.-)\n*$")
end
return json.encode(anthropic_req)
end
-- ============================================================
-- transform_response (Anthropic → OpenAI, non-streaming)
-- ============================================================
function adapter.transform_response(raw_body)
local ok, resp = pcall(json.decode, raw_body)
if not ok or resp == nil then return raw_body end
local unified = {
content = "",
finish_reason = "",
token_usage = { prompt = 0, completion = 0, total = 0 },
}
if resp.usage then
unified.token_usage.prompt = resp.usage.input_tokens or 0
unified.token_usage.completion = resp.usage.output_tokens or 0
unified.token_usage.total = (resp.usage.input_tokens or 0) + (resp.usage.output_tokens or 0)
-- Emit details whenever Anthropic reports the field, even at 0, so a
-- reported cache miss stays distinguishable from "not reported".
if resp.usage.cache_read_input_tokens ~= nil then
unified.token_usage.prompt_tokens_details = {
cached_tokens = resp.usage.cache_read_input_tokens
}
end
end
if resp.content and #resp.content > 0 then
local tcs = {}
for _, block in ipairs(resp.content) do
if block.type == "text" then
unified.content = unified.content .. (block.text or "")
elseif block.type == "thinking" and block.thinking then
unified.reasoning_content = (unified.reasoning_content or "") .. block.thinking
elseif block.type == "tool_use" then
table.insert(tcs, {
id = safe_tool_id(block.id),
type = "function",
name = block.name or "",
arguments = block.input or {},
})
end
end
if #tcs > 0 then unified.tool_calls = tcs end
end
unified.finish_reason = resp.stop_reason or ""
if unified.finish_reason == "tool_use" then
unified.finish_reason = "tool_calls"
elseif unified.finish_reason == "max_tokens" then
unified.finish_reason = "length"
elseif unified.finish_reason == "end_turn"
or unified.finish_reason == "stop_sequence" then
unified.finish_reason = "stop"
end
return json.encode(unified)
end
-- ============================================================
-- transform_stream_chunk (Anthropic SSE → OpenAI SSE delta)
-- ============================================================
function adapter.transform_stream_chunk(raw_chunk)
local ok, chunk = pcall(json.decode, raw_chunk)
if not ok then return "" end
-- ── message_start: initial usage ─────────────────────────
if chunk.type == "message_start" then
if chunk.message and type(chunk.message.usage) == "table" then
local u = chunk.message.usage
local p = u.input_tokens or 0
local c = u.output_tokens or 0
if p > 0 or c > 0 then
local uses = { prompt = p, completion = c, total = p + c }
if u.cache_read_input_tokens ~= nil then
uses.prompt_tokens_details = {
cached_tokens = u.cache_read_input_tokens
}
end
return json.encode({ usage = uses, done = false })
end
end
return ""
end
-- ── message_delta: stop_reason + final usage ─────────────
if chunk.type == "message_delta" then
local finish = nil
if chunk.delta and chunk.delta.stop_reason ~= nil then
local sr = chunk.delta.stop_reason
if sr == "max_tokens" then
finish = "length"
elseif sr == "tool_use" then
finish = "tool_calls"
else
finish = "stop"
end
end
local uses = nil
if type(chunk.usage) == "table" then
local u = chunk.usage
local p = u.input_tokens or 0
local c = u.output_tokens or 0
if p > 0 or c > 0 then
uses = { prompt = p, completion = c, total = p + c }
end
end
if uses ~= nil then
return json.encode({ content = "", done = (finish ~= nil), finish_reason = finish, usage = uses })
end
return json.encode({ content = "", done = (finish ~= nil), finish_reason = finish })
end
-- ── content_block_start: begin text / thinking / tool_use ─
if chunk.type == "content_block_start" and chunk.content_block then
local cb = chunk.content_block
if cb.type == "tool_use" then
-- Pass Anthropic content_block index through; Go-side rewrites
-- to sequential OpenAI tool_call ordinal for multi-tool streams.
return json.encode({
content = "", done = false,
tool_calls = { {
index = chunk.index or 0,
id = safe_tool_id(cb.id),
type = "function",
["function"] = { name = cb.name or "", arguments = "" },
} },
})
end
return "" -- text / thinking block start: no OpenAI equivalent
end
-- ── content_block_delta: incremental content ──────────────
if chunk.type == "content_block_delta" and chunk.delta then
local d = chunk.delta
if d.type == "input_json_delta" then
-- Tool call argument fragment; Go-side rewrites index.
return json.encode({
content = "", done = false,
tool_calls = { {
index = chunk.index or 0,
id = "",
type = "function",
["function"] = { name = "", arguments = d.partial_json or "" },
} },
})
end
if d.type == "thinking_delta" and d.thinking then
return json.encode({ content = "", done = false, reasoning_content = d.thinking })
end
if d.type == "text_delta" and d.text then
return json.encode({ content = d.text, done = false })
end
end
-- ── content_block_stop / message_stop ─────────────────────
if chunk.type == "message_stop" then
-- The message_delta event already emitted the true finish_reason.
-- Do NOT emit done=true here: an empty finish_reason would
-- overwrite the real one (tool_calls) in the Go gateway's
-- lastFinish tracker, causing the final SSE chunk to say
-- finish_reason=stop instead of tool_calls.
return ""
end
return ""
end
-- ============================================================
-- transform_error (Anthropic error → human-readable string)
-- ============================================================
function adapter.transform_error(status, body)
local ok, resp = pcall(json.decode, body)
if not ok or type(resp) ~= "table" then return nil end
-- Anthropic envelope: {type:"error", error:{type, message}}
if resp.type == "error" and type(resp.error) == "table"
and type(resp.error.message) == "string" then
return resp.error.message
end
-- Flat envelope: {error: {message: "..."}}
if type(resp.error) == "table" and type(resp.error.message) == "string" then
return resp.error.message
end
return nil
end
return adapter