brazen 0.0.4

A stateless, swiss-army-knife adapter for every LLM provider and protocol.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205

//! The `messages[]` / `system` folds (anthropic-messages §2.3–§2.5, inverted): the
//! top-level `system` (string | text blocks) → `req.system`; each wire message → one
//! canonical `Message`. A `"user"` message bearing any `tool_result` block is a
//! `Role::Tool` turn (Anthropic packs tool results into user turns, §2.3); every other
//! `"user"` message is `Role::User`, `"assistant"` is `Role::Assistant`. Content parts
//! invert per §2.5 — thinking `signature`, `redacted_thinking` `data`, and the two
//! server-tool blocks all decode VERBATIM (the dialect carries them natively, so the
//! replay stash stays idle here). Per-block `cache_control` marks are the encoder's own
//! automatic policy (§2.10) with no canonical home → ignored (tolerant reader).

use serde_json::Value;

use super::{arr_of, bad, err, obj_of, opt_str, str_of};
use crate::canonical::{CanonicalRequest, Content, DocumentSource, ImageSource, Message, Role};
use crate::ingress::IngressError;

/// Fold the wire `messages` array into `req.messages`.
pub(super) fn fold(v: &Value, req: &mut CanonicalRequest) -> Result<(), IngressError> {
    for (i, m) in arr_of(Some(v), "messages")?.iter().enumerate() {
        let path = format!("messages[{i}]");
        let obj = obj_of(Some(m), &path)?;
        let content = parts(obj.get("content"), &path)?;
        let role = match str_of(obj.get("role"), &format!("{path}.role"))? {
            "assistant" => Role::Assistant,
            // A tool-result-bearing user turn is the canonical `Role::Tool` (§2.3);
            // any other user turn is `Role::User` — the inverse of the egress
            // `Role::Tool` → `"user"` + `tool_result` projection.
            "user" if content.iter().any(is_tool_result) => Role::Tool,
            "user" => Role::User,
            other => {
                return Err(err(format!(
                    "`{path}.role` \"{other}\" is not a messages role"
                )))
            }
        };
        req.messages.push(Message { role, content });
    }
    Ok(())
}

/// The top-level `system` (§2.4, inverted): a bare string or an array of TEXT blocks
/// → `Vec<Content::Text>`. The wire `system` is a text-only slot (the automatic head
/// cache mark rides it, ignored here); a non-text block has no canonical projection
/// in this slot → rung 4.
pub(super) fn system(v: &Value) -> Result<Vec<Content>, IngressError> {
    match v {
        Value::String(s) => Ok(vec![Content::Text(s.clone())]),
        Value::Array(a) => a
            .iter()
            .enumerate()
            .map(|(i, b)| {
                let path = format!("system[{i}]");
                match str_of(obj_of(Some(b), &path)?.get("type"), &format!("{path}.type"))? {
                    "text" => Ok(Content::Text(
                        str_of(b.get("text"), &format!("{path}.text"))?.to_owned(),
                    )),
                    other => Err(err(format!(
                        "`{path}.type` \"{other}\" has no canonical projection in the text-only system slot"
                    ))),
                }
            })
            .collect(),
        _ => Err(bad("system", "a string or an array of text blocks")),
    }
}

fn is_tool_result(c: &Content) -> bool {
    matches!(c, Content::ToolResult { .. })
}

/// A wire `content` value → canonical parts: a bare string is one `Text` (the
/// string-vs-list distinction dies at decode, arch §3.1); an array maps per block.
fn parts(v: Option<&Value>, path: &str) -> Result<Vec<Content>, IngressError> {
    match v {
        Some(Value::String(s)) => Ok(vec![Content::Text(s.clone())]),
        Some(Value::Array(a)) => a
            .iter()
            .enumerate()
            .map(|(i, p)| block(p, &format!("{path}.content[{i}]")))
            .collect(),
        _ => Err(bad(
            &format!("{path}.content"),
            "a string or an array of content blocks",
        )),
    }
}

/// One wire ContentBlockParam → one `Content` (§2.5, inverted). Thinking/redacted/
/// server-tool blocks decode VERBATIM (the dialect carries them natively).
fn block(p: &Value, path: &str) -> Result<Content, IngressError> {
    let obj = obj_of(Some(p), path)?;
    let ty = str_of(obj.get("type"), &format!("{path}.type"))?;
    Ok(match ty {
        "text" => Content::Text(str_of(obj.get("text"), &format!("{path}.text"))?.to_owned()),
        "image" => Content::Image {
            source: image_source(obj.get("source"), &format!("{path}.source"))?,
        },
        "document" => Content::Document {
            source: document_source(obj.get("source"), &format!("{path}.source"))?,
        },
        "tool_use" => Content::ToolUse {
            id: str_of(obj.get("id"), &format!("{path}.id"))?.to_owned(),
            name: str_of(obj.get("name"), &format!("{path}.name"))?.to_owned(),
            input: obj.get("input").cloned().unwrap_or(Value::Null),
            signature: None,
        },
        "tool_result" => Content::ToolResult {
            tool_use_id: str_of(obj.get("tool_use_id"), &format!("{path}.tool_use_id"))?.to_owned(),
            content: tool_result_content(obj.get("content"), path)?,
            is_error: obj.get("is_error") == Some(&Value::Bool(true)),
        },
        "thinking" => Content::Thinking {
            text: str_of(obj.get("thinking"), &format!("{path}.thinking"))?.to_owned(),
            signature: opt_str(obj.get("signature"), &format!("{path}.signature"))?,
            id: None,
            encrypted_content: None,
        },
        "redacted_thinking" => Content::RedactedThinking {
            data: str_of(obj.get("data"), &format!("{path}.data"))?.to_owned(),
        },
        "server_tool_use" => Content::ServerToolUse {
            id: str_of(obj.get("id"), &format!("{path}.id"))?.to_owned(),
            name: str_of(obj.get("name"), &format!("{path}.name"))?.to_owned(),
            input: obj.get("input").cloned().unwrap_or(Value::Null),
        },
        // The open `*_tool_result` family (§2.5): the tag is carried as `kind` data,
        // suffix-matched exactly as decode does, `content` whole — zero per-tool knowledge.
        t if t.ends_with("_tool_result") => Content::ServerToolResult {
            kind: t.to_owned(),
            tool_use_id: str_of(obj.get("tool_use_id"), &format!("{path}.tool_use_id"))?.to_owned(),
            content: obj.get("content").cloned().unwrap_or(Value::Null),
        },
        other => {
            return Err(err(format!(
                "`{path}.type` \"{other}\" has no canonical projection"
            )))
        }
    })
}

/// `tool_result.content` (§2.5, inverted): a text/image-only slot — a bare string, or
/// an array of text/image blocks. Any other nested block is unrepresentable → rung 4.
fn tool_result_content(v: Option<&Value>, path: &str) -> Result<Vec<Content>, IngressError> {
    match v {
        Some(Value::String(s)) => Ok(vec![Content::Text(s.clone())]),
        Some(Value::Array(a)) => a
            .iter()
            .enumerate()
            .map(|(i, b)| {
                let bp = format!("{path}.content[{i}]");
                let obj = obj_of(Some(b), &bp)?;
                match str_of(obj.get("type"), &format!("{bp}.type"))? {
                    "text" => Ok(Content::Text(
                        str_of(obj.get("text"), &format!("{bp}.text"))?.to_owned(),
                    )),
                    "image" => Ok(Content::Image {
                        source: image_source(obj.get("source"), &format!("{bp}.source"))?,
                    }),
                    other => Err(err(format!(
                        "`{bp}.type` \"{other}\" has no canonical projection in the tool_result slot"
                    ))),
                }
            })
            .collect(),
        _ => Err(bad(
            &format!("{path}.content"),
            "a string or an array of text/image blocks",
        )),
    }
}

/// A wire image `source` → the canonical source (§2.5): `base64` (media_type+data) or
/// `url`. The wire tags on `type`; the canonical enum tags on `kind`.
fn image_source(v: Option<&Value>, path: &str) -> Result<ImageSource, IngressError> {
    let o = obj_of(v, path)?;
    match str_of(o.get("type"), &format!("{path}.type"))? {
        "base64" => Ok(ImageSource::Base64 {
            media_type: str_of(o.get("media_type"), &format!("{path}.media_type"))?.to_owned(),
            data: str_of(o.get("data"), &format!("{path}.data"))?.to_owned(),
        }),
        "url" => Ok(ImageSource::Url {
            url: str_of(o.get("url"), &format!("{path}.url"))?.to_owned(),
        }),
        other => Err(err(format!(
            "`{path}.type` \"{other}\" is not a representable image source"
        ))),
    }
}

/// A wire document `source` → the canonical source (§2.5): `base64` or `url`.
fn document_source(v: Option<&Value>, path: &str) -> Result<DocumentSource, IngressError> {
    let o = obj_of(v, path)?;
    match str_of(o.get("type"), &format!("{path}.type"))? {
        "base64" => Ok(DocumentSource::Base64 {
            media_type: str_of(o.get("media_type"), &format!("{path}.media_type"))?.to_owned(),
            data: str_of(o.get("data"), &format!("{path}.data"))?.to_owned(),
        }),
        "url" => Ok(DocumentSource::Url {
            url: str_of(o.get("url"), &format!("{path}.url"))?.to_owned(),
        }),
        other => Err(err(format!(
            "`{path}.type` \"{other}\" is not a representable document source"
        ))),
    }
}