rig/tool/
mod.rs

1//! Module defining tool related structs and traits.
2//!
3//! The [Tool] trait defines a simple interface for creating tools that can be used
4//! by [Agents](crate::agent::Agent).
5//!
6//! The [ToolEmbedding] trait extends the [Tool] trait to allow for tools that can be
7//! stored in a vector store and RAGged.
8//!
9//! The [ToolSet] struct is a collection of tools that can be used by an [Agent](crate::agent::Agent)
10//! and optionally RAGged.
11
12pub mod server;
13use std::collections::HashMap;
14use std::fmt;
15
16use futures::Future;
17use serde::{Deserialize, Serialize};
18
19use crate::{
20    completion::{self, ToolDefinition},
21    embeddings::{embed::EmbedError, tool::ToolSchema},
22    wasm_compat::{WasmBoxedFuture, WasmCompatSend, WasmCompatSync},
23};
24
25#[derive(Debug, thiserror::Error)]
26pub enum ToolError {
27    #[cfg(not(target_family = "wasm"))]
28    /// Error returned by the tool
29    ToolCallError(#[from] Box<dyn std::error::Error + Send + Sync>),
30
31    #[cfg(target_family = "wasm")]
32    /// Error returned by the tool
33    ToolCallError(#[from] Box<dyn std::error::Error>),
34    /// Error caused by a de/serialization fail
35    JsonError(#[from] serde_json::Error),
36}
37
38impl fmt::Display for ToolError {
39    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
40        match self {
41            ToolError::ToolCallError(e) => {
42                let error_str = e.to_string();
43                // This is required due to being able to use agents as tools
44                // which means it is possible to get recursive tool call errors
45                if error_str.starts_with("ToolCallError: ") {
46                    write!(f, "{}", error_str)
47                } else {
48                    write!(f, "ToolCallError: {}", error_str)
49                }
50            }
51            ToolError::JsonError(e) => write!(f, "JsonError: {e}"),
52        }
53    }
54}
55
56/// Trait that represents a simple LLM tool
57///
58/// # Example
59/// ```
60/// use rig::{
61///     completion::ToolDefinition,
62///     tool::{ToolSet, Tool},
63/// };
64///
65/// #[derive(serde::Deserialize)]
66/// struct AddArgs {
67///     x: i32,
68///     y: i32,
69/// }
70///
71/// #[derive(Debug, thiserror::Error)]
72/// #[error("Math error")]
73/// struct MathError;
74///
75/// #[derive(serde::Deserialize, serde::Serialize)]
76/// struct Adder;
77///
78/// impl Tool for Adder {
79///     const NAME: &'static str = "add";
80///
81///     type Error = MathError;
82///     type Args = AddArgs;
83///     type Output = i32;
84///
85///     async fn definition(&self, _prompt: String) -> ToolDefinition {
86///         ToolDefinition {
87///             name: "add".to_string(),
88///             description: "Add x and y together".to_string(),
89///             parameters: serde_json::json!({
90///                 "type": "object",
91///                 "properties": {
92///                     "x": {
93///                         "type": "number",
94///                         "description": "The first number to add"
95///                     },
96///                     "y": {
97///                         "type": "number",
98///                         "description": "The second number to add"
99///                     }
100///                 }
101///             })
102///         }
103///     }
104///
105///     async fn call(&self, args: Self::Args) -> Result<Self::Output, Self::Error> {
106///         let result = args.x + args.y;
107///         Ok(result)
108///     }
109/// }
110/// ```
111pub trait Tool: Sized + WasmCompatSend + WasmCompatSync {
112    /// The name of the tool. This name should be unique.
113    const NAME: &'static str;
114
115    /// The error type of the tool.
116    type Error: std::error::Error + WasmCompatSend + WasmCompatSync + 'static;
117    /// The arguments type of the tool.
118    type Args: for<'a> Deserialize<'a> + WasmCompatSend + WasmCompatSync;
119    /// The output type of the tool.
120    type Output: Serialize;
121
122    /// A method returning the name of the tool.
123    fn name(&self) -> String {
124        Self::NAME.to_string()
125    }
126
127    /// A method returning the tool definition. The user prompt can be used to
128    /// tailor the definition to the specific use case.
129    fn definition(
130        &self,
131        _prompt: String,
132    ) -> impl Future<Output = ToolDefinition> + WasmCompatSend + WasmCompatSync;
133
134    /// The tool execution method.
135    /// Both the arguments and return value are a String since these values are meant to
136    /// be the output and input of LLM models (respectively)
137    fn call(
138        &self,
139        args: Self::Args,
140    ) -> impl Future<Output = Result<Self::Output, Self::Error>> + WasmCompatSend;
141}
142
143/// Trait that represents an LLM tool that can be stored in a vector store and RAGged
144pub trait ToolEmbedding: Tool {
145    type InitError: std::error::Error + WasmCompatSend + WasmCompatSync + 'static;
146
147    /// Type of the tool' context. This context will be saved and loaded from the
148    /// vector store when ragging the tool.
149    /// This context can be used to store the tool's static configuration and local
150    /// context.
151    type Context: for<'a> Deserialize<'a> + Serialize;
152
153    /// Type of the tool's state. This state will be passed to the tool when initializing it.
154    /// This state can be used to pass runtime arguments to the tool such as clients,
155    /// API keys and other configuration.
156    type State: WasmCompatSend;
157
158    /// A method returning the documents that will be used as embeddings for the tool.
159    /// This allows for a tool to be retrieved from multiple embedding "directions".
160    /// If the tool will not be RAGged, this method should return an empty vector.
161    fn embedding_docs(&self) -> Vec<String>;
162
163    /// A method returning the context of the tool.
164    fn context(&self) -> Self::Context;
165
166    /// A method to initialize the tool from the context, and a state.
167    fn init(state: Self::State, context: Self::Context) -> Result<Self, Self::InitError>;
168}
169
170/// Wrapper trait to allow for dynamic dispatch of simple tools
171pub trait ToolDyn: WasmCompatSend + WasmCompatSync {
172    fn name(&self) -> String;
173
174    fn definition<'a>(&'a self, prompt: String) -> WasmBoxedFuture<'a, ToolDefinition>;
175
176    fn call<'a>(&'a self, args: String) -> WasmBoxedFuture<'a, Result<String, ToolError>>;
177}
178
179impl<T: Tool> ToolDyn for T {
180    fn name(&self) -> String {
181        self.name()
182    }
183
184    fn definition<'a>(&'a self, prompt: String) -> WasmBoxedFuture<'a, ToolDefinition> {
185        Box::pin(<Self as Tool>::definition(self, prompt))
186    }
187
188    fn call<'a>(&'a self, args: String) -> WasmBoxedFuture<'a, Result<String, ToolError>> {
189        Box::pin(async move {
190            match serde_json::from_str(&args) {
191                Ok(args) => <Self as Tool>::call(self, args)
192                    .await
193                    .map_err(|e| ToolError::ToolCallError(Box::new(e)))
194                    .and_then(|output| {
195                        serde_json::to_string(&output).map_err(ToolError::JsonError)
196                    }),
197                Err(e) => Err(ToolError::JsonError(e)),
198            }
199        })
200    }
201}
202
203#[cfg(feature = "rmcp")]
204#[cfg_attr(docsrs, doc(cfg(feature = "rmcp")))]
205pub mod rmcp {
206    use crate::completion::ToolDefinition;
207    use crate::tool::ToolDyn;
208    use crate::tool::ToolError;
209    use crate::wasm_compat::WasmBoxedFuture;
210    use rmcp::model::RawContent;
211    use std::borrow::Cow;
212
213    #[derive(Clone)]
214    pub struct McpTool {
215        definition: rmcp::model::Tool,
216        client: rmcp::service::ServerSink,
217    }
218
219    impl McpTool {
220        pub fn from_mcp_server(
221            definition: rmcp::model::Tool,
222            client: rmcp::service::ServerSink,
223        ) -> Self {
224            Self { definition, client }
225        }
226    }
227
228    impl From<&rmcp::model::Tool> for ToolDefinition {
229        fn from(val: &rmcp::model::Tool) -> Self {
230            Self {
231                name: val.name.to_string(),
232                description: val.description.clone().unwrap_or(Cow::from("")).to_string(),
233                parameters: val.schema_as_json_value(),
234            }
235        }
236    }
237
238    impl From<rmcp::model::Tool> for ToolDefinition {
239        fn from(val: rmcp::model::Tool) -> Self {
240            Self {
241                name: val.name.to_string(),
242                description: val.description.clone().unwrap_or(Cow::from("")).to_string(),
243                parameters: val.schema_as_json_value(),
244            }
245        }
246    }
247
248    #[derive(Debug, thiserror::Error)]
249    #[error("MCP tool error: {0}")]
250    pub struct McpToolError(String);
251
252    impl From<McpToolError> for ToolError {
253        fn from(e: McpToolError) -> Self {
254            ToolError::ToolCallError(Box::new(e))
255        }
256    }
257
258    impl ToolDyn for McpTool {
259        fn name(&self) -> String {
260            self.definition.name.to_string()
261        }
262
263        fn definition(&self, _prompt: String) -> WasmBoxedFuture<'_, ToolDefinition> {
264            Box::pin(async move {
265                ToolDefinition {
266                    name: self.definition.name.to_string(),
267                    description: self
268                        .definition
269                        .description
270                        .clone()
271                        .unwrap_or(Cow::from(""))
272                        .to_string(),
273                    parameters: serde_json::to_value(&self.definition.input_schema)
274                        .unwrap_or_default(),
275                }
276            })
277        }
278
279        fn call(&self, args: String) -> WasmBoxedFuture<'_, Result<String, ToolError>> {
280            let name = self.definition.name.clone();
281            let arguments = serde_json::from_str(&args).unwrap_or_default();
282
283            Box::pin(async move {
284                let result = self
285                    .client
286                    .call_tool(rmcp::model::CallToolRequestParam { name, arguments })
287                    .await
288                    .map_err(|e| McpToolError(format!("Tool returned an error: {e}")))?;
289
290                if let Some(true) = result.is_error {
291                    let error_msg = result
292                        .content
293                        .into_iter()
294                        .map(|x| x.raw.as_text().map(|y| y.to_owned()))
295                        .map(|x| x.map(|x| x.clone().text))
296                        .collect::<Option<Vec<String>>>();
297
298                    let error_message = error_msg.map(|x| x.join("\n"));
299                    if let Some(error_message) = error_message {
300                        return Err(McpToolError(error_message).into());
301                    } else {
302                        return Err(McpToolError("No message returned".to_string()).into());
303                    }
304                };
305
306                Ok(result
307                    .content
308                    .into_iter()
309                    .map(|c| match c.raw {
310                        rmcp::model::RawContent::Text(raw) => raw.text,
311                        rmcp::model::RawContent::Image(raw) => {
312                            format!("data:{};base64,{}", raw.mime_type, raw.data)
313                        }
314                        rmcp::model::RawContent::Resource(raw) => match raw.resource {
315                            rmcp::model::ResourceContents::TextResourceContents {
316                                uri,
317                                mime_type,
318                                text,
319                                ..
320                            } => {
321                                format!(
322                                    "{mime_type}{uri}:{text}",
323                                    mime_type = mime_type
324                                        .map(|m| format!("data:{m};"))
325                                        .unwrap_or_default(),
326                                )
327                            }
328                            rmcp::model::ResourceContents::BlobResourceContents {
329                                uri,
330                                mime_type,
331                                blob,
332                                ..
333                            } => format!(
334                                "{mime_type}{uri}:{blob}",
335                                mime_type = mime_type
336                                    .map(|m| format!("data:{m};"))
337                                    .unwrap_or_default(),
338                            ),
339                        },
340                        RawContent::Audio(_) => {
341                            panic!("Support for audio results from an MCP tool is currently unimplemented. Come back later!")
342                        }
343                        thing => {
344                            panic!("Unsupported type found: {thing:?}")
345                        }
346                    })
347                    .collect::<String>())
348            })
349        }
350    }
351}
352
353/// Wrapper trait to allow for dynamic dispatch of raggable tools
354pub trait ToolEmbeddingDyn: ToolDyn {
355    fn context(&self) -> serde_json::Result<serde_json::Value>;
356
357    fn embedding_docs(&self) -> Vec<String>;
358}
359
360impl<T> ToolEmbeddingDyn for T
361where
362    T: ToolEmbedding + 'static,
363{
364    fn context(&self) -> serde_json::Result<serde_json::Value> {
365        serde_json::to_value(self.context())
366    }
367
368    fn embedding_docs(&self) -> Vec<String> {
369        self.embedding_docs()
370    }
371}
372
373pub(crate) enum ToolType {
374    Simple(Box<dyn ToolDyn>),
375    Embedding(Box<dyn ToolEmbeddingDyn>),
376}
377
378impl ToolType {
379    pub fn name(&self) -> String {
380        match self {
381            ToolType::Simple(tool) => tool.name(),
382            ToolType::Embedding(tool) => tool.name(),
383        }
384    }
385
386    pub async fn definition(&self, prompt: String) -> ToolDefinition {
387        match self {
388            ToolType::Simple(tool) => tool.definition(prompt).await,
389            ToolType::Embedding(tool) => tool.definition(prompt).await,
390        }
391    }
392
393    pub async fn call(&self, args: String) -> Result<String, ToolError> {
394        match self {
395            ToolType::Simple(tool) => tool.call(args).await,
396            ToolType::Embedding(tool) => tool.call(args).await,
397        }
398    }
399}
400
401#[derive(Debug, thiserror::Error)]
402pub enum ToolSetError {
403    /// Error returned by the tool
404    #[error("ToolCallError: {0}")]
405    ToolCallError(#[from] ToolError),
406
407    /// Could not find a tool
408    #[error("ToolNotFoundError: {0}")]
409    ToolNotFoundError(String),
410
411    // TODO: Revisit this
412    #[error("JsonError: {0}")]
413    JsonError(#[from] serde_json::Error),
414
415    /// Tool call was interrupted. Primarily useful for agent multi-step/turn prompting.
416    #[error("Tool call interrupted")]
417    Interrupted,
418}
419
420/// A struct that holds a set of tools
421#[derive(Default)]
422pub struct ToolSet {
423    pub(crate) tools: HashMap<String, ToolType>,
424}
425
426impl ToolSet {
427    /// Create a new ToolSet from a list of tools
428    pub fn from_tools(tools: Vec<impl ToolDyn + 'static>) -> Self {
429        let mut toolset = Self::default();
430        tools.into_iter().for_each(|tool| {
431            toolset.add_tool(tool);
432        });
433        toolset
434    }
435
436    /// Create a toolset builder
437    pub fn builder() -> ToolSetBuilder {
438        ToolSetBuilder::default()
439    }
440
441    /// Check if the toolset contains a tool with the given name
442    pub fn contains(&self, toolname: &str) -> bool {
443        self.tools.contains_key(toolname)
444    }
445
446    /// Add a tool to the toolset
447    pub fn add_tool(&mut self, tool: impl ToolDyn + 'static) {
448        self.tools
449            .insert(tool.name(), ToolType::Simple(Box::new(tool)));
450    }
451
452    /// Adds a boxed tool to the toolset. Useful for situations when dynamic dispatch is required.
453    pub fn add_tool_boxed(&mut self, tool: Box<dyn ToolDyn>) {
454        self.tools.insert(tool.name(), ToolType::Simple(tool));
455    }
456
457    pub fn delete_tool(&mut self, tool_name: &str) {
458        let _ = self.tools.remove(tool_name);
459    }
460
461    /// Merge another toolset into this one
462    pub fn add_tools(&mut self, toolset: ToolSet) {
463        self.tools.extend(toolset.tools);
464    }
465
466    pub(crate) fn get(&self, toolname: &str) -> Option<&ToolType> {
467        self.tools.get(toolname)
468    }
469
470    pub async fn get_tool_definitions(&self) -> Result<Vec<ToolDefinition>, ToolSetError> {
471        let mut defs = Vec::new();
472        for tool in self.tools.values() {
473            let def = tool.definition(String::new()).await;
474            defs.push(def);
475        }
476        Ok(defs)
477    }
478
479    /// Call a tool with the given name and arguments
480    pub async fn call(&self, toolname: &str, args: String) -> Result<String, ToolSetError> {
481        if let Some(tool) = self.tools.get(toolname) {
482            tracing::debug!(target: "rig",
483                "Calling tool {toolname} with args:\n{}",
484                serde_json::to_string_pretty(&args).unwrap()
485            );
486            Ok(tool.call(args).await?)
487        } else {
488            Err(ToolSetError::ToolNotFoundError(toolname.to_string()))
489        }
490    }
491
492    /// Get the documents of all the tools in the toolset
493    pub async fn documents(&self) -> Result<Vec<completion::Document>, ToolSetError> {
494        let mut docs = Vec::new();
495        for tool in self.tools.values() {
496            match tool {
497                ToolType::Simple(tool) => {
498                    docs.push(completion::Document {
499                        id: tool.name(),
500                        text: format!(
501                            "\
502                            Tool: {}\n\
503                            Definition: \n\
504                            {}\
505                        ",
506                            tool.name(),
507                            serde_json::to_string_pretty(&tool.definition("".to_string()).await)?
508                        ),
509                        additional_props: HashMap::new(),
510                    });
511                }
512                ToolType::Embedding(tool) => {
513                    docs.push(completion::Document {
514                        id: tool.name(),
515                        text: format!(
516                            "\
517                            Tool: {}\n\
518                            Definition: \n\
519                            {}\
520                        ",
521                            tool.name(),
522                            serde_json::to_string_pretty(&tool.definition("".to_string()).await)?
523                        ),
524                        additional_props: HashMap::new(),
525                    });
526                }
527            }
528        }
529        Ok(docs)
530    }
531
532    /// Convert tools in self to objects of type ToolSchema.
533    /// This is necessary because when adding tools to the EmbeddingBuilder because all
534    /// documents added to the builder must all be of the same type.
535    pub fn schemas(&self) -> Result<Vec<ToolSchema>, EmbedError> {
536        self.tools
537            .values()
538            .filter_map(|tool_type| {
539                if let ToolType::Embedding(tool) = tool_type {
540                    Some(ToolSchema::try_from(&**tool))
541                } else {
542                    None
543                }
544            })
545            .collect::<Result<Vec<_>, _>>()
546    }
547}
548
549#[derive(Default)]
550pub struct ToolSetBuilder {
551    tools: Vec<ToolType>,
552}
553
554impl ToolSetBuilder {
555    pub fn static_tool(mut self, tool: impl ToolDyn + 'static) -> Self {
556        self.tools.push(ToolType::Simple(Box::new(tool)));
557        self
558    }
559
560    pub fn dynamic_tool(mut self, tool: impl ToolEmbeddingDyn + 'static) -> Self {
561        self.tools.push(ToolType::Embedding(Box::new(tool)));
562        self
563    }
564
565    pub fn build(self) -> ToolSet {
566        ToolSet {
567            tools: self
568                .tools
569                .into_iter()
570                .map(|tool| (tool.name(), tool))
571                .collect(),
572        }
573    }
574}
575
576#[cfg(test)]
577mod tests {
578    use serde_json::json;
579
580    use super::*;
581
582    fn get_test_toolset() -> ToolSet {
583        let mut toolset = ToolSet::default();
584
585        #[derive(Deserialize)]
586        struct OperationArgs {
587            x: i32,
588            y: i32,
589        }
590
591        #[derive(Debug, thiserror::Error)]
592        #[error("Math error")]
593        struct MathError;
594
595        #[derive(Deserialize, Serialize)]
596        struct Adder;
597
598        impl Tool for Adder {
599            const NAME: &'static str = "add";
600            type Error = MathError;
601            type Args = OperationArgs;
602            type Output = i32;
603
604            async fn definition(&self, _prompt: String) -> ToolDefinition {
605                ToolDefinition {
606                    name: "add".to_string(),
607                    description: "Add x and y together".to_string(),
608                    parameters: json!({
609                        "type": "object",
610                        "properties": {
611                            "x": {
612                                "type": "number",
613                                "description": "The first number to add"
614                            },
615                            "y": {
616                                "type": "number",
617                                "description": "The second number to add"
618                            }
619                        },
620                        "required": ["x", "y"]
621                    }),
622                }
623            }
624
625            async fn call(&self, args: Self::Args) -> Result<Self::Output, Self::Error> {
626                let result = args.x + args.y;
627                Ok(result)
628            }
629        }
630
631        #[derive(Deserialize, Serialize)]
632        struct Subtract;
633
634        impl Tool for Subtract {
635            const NAME: &'static str = "subtract";
636            type Error = MathError;
637            type Args = OperationArgs;
638            type Output = i32;
639
640            async fn definition(&self, _prompt: String) -> ToolDefinition {
641                serde_json::from_value(json!({
642                    "name": "subtract",
643                    "description": "Subtract y from x (i.e.: x - y)",
644                    "parameters": {
645                        "type": "object",
646                        "properties": {
647                            "x": {
648                                "type": "number",
649                                "description": "The number to subtract from"
650                            },
651                            "y": {
652                                "type": "number",
653                                "description": "The number to subtract"
654                            }
655                        },
656                        "required": ["x", "y"]
657                    }
658                }))
659                .expect("Tool Definition")
660            }
661
662            async fn call(&self, args: Self::Args) -> Result<Self::Output, Self::Error> {
663                let result = args.x - args.y;
664                Ok(result)
665            }
666        }
667
668        toolset.add_tool(Adder);
669        toolset.add_tool(Subtract);
670        toolset
671    }
672
673    #[tokio::test]
674    async fn test_get_tool_definitions() {
675        let toolset = get_test_toolset();
676        let tools = toolset.get_tool_definitions().await.unwrap();
677        assert_eq!(tools.len(), 2);
678    }
679
680    #[test]
681    fn test_tool_deletion() {
682        let mut toolset = get_test_toolset();
683        assert_eq!(toolset.tools.len(), 2);
684        toolset.delete_tool("add");
685        assert!(!toolset.contains("add"));
686        assert_eq!(toolset.tools.len(), 1);
687    }
688}
rig/tool/mod.rs

rig/tool/
mod.rs
