patchloom 0.11.0

Structured file editing library and CLI for AI agents: parser-backed JSON/YAML/TOML edits, AST-aware code operations, multi-file batching, markdown operations, and MCP server
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

//! Resource limits and input validation for MCP tools.

use rmcp::model::ErrorData as McpError;

pub(super) fn default_strict_true() -> bool {
    true
}

// ---------------------------------------------------------------------------
// Resource limits
// ---------------------------------------------------------------------------

/// Maximum size for content/diff fields (10 MiB).
pub(super) const MAX_CONTENT_BYTES: usize = 10 * 1024 * 1024;

/// Maximum size for pattern/selector string fields (1 MiB).
pub(super) const MAX_PARAM_BYTES: usize = 1024 * 1024;

/// Maximum number of files in a batch operation.
pub(super) const MAX_BATCH_FILES: usize = 1000;

/// Maximum nesting depth for JSON value parameters.
pub(super) const MAX_JSON_DEPTH: usize = 64;

pub(super) fn validate_size(field: &str, value: &str, max_bytes: usize) -> Result<(), McpError> {
    if value.len() > max_bytes {
        return Err(McpError::invalid_params(
            format!(
                "{field} exceeds maximum size ({} bytes, limit {max_bytes})",
                value.len(),
            ),
            None,
        ));
    }
    Ok(())
}

pub(super) fn validate_content_size(field: &str, value: &str) -> Result<(), McpError> {
    validate_size(field, value, MAX_CONTENT_BYTES)
}

pub(super) fn validate_param_size(field: &str, value: &str) -> Result<(), McpError> {
    validate_size(field, value, MAX_PARAM_BYTES)
}

pub(super) fn validate_json_depth(field: &str, value: &serde_json::Value) -> Result<(), McpError> {
    fn measure(v: &serde_json::Value) -> usize {
        match v {
            serde_json::Value::Array(arr) => 1 + arr.iter().map(measure).max().unwrap_or(0),
            serde_json::Value::Object(obj) => 1 + obj.values().map(measure).max().unwrap_or(0),
            _ => 0,
        }
    }
    let depth = measure(value);
    if depth > MAX_JSON_DEPTH {
        return Err(McpError::invalid_params(
            format!("{field} exceeds maximum nesting depth ({depth}, limit {MAX_JSON_DEPTH})"),
            None,
        ));
    }
    Ok(())
}

pub(super) fn validate_batch_size(field: &str, count: usize) -> Result<(), McpError> {
    if count > MAX_BATCH_FILES {
        return Err(McpError::invalid_params(
            format!("{field} exceeds maximum batch size ({count}, limit {MAX_BATCH_FILES})"),
            None,
        ));
    }
    Ok(())
}