From 700f9baed17f507217bb29aeacd3c92ec8e83552 Mon Sep 17 00:00:00 2001
From: Jon Klein <kleintech@gmail.com>
Date: Wed, 13 May 2026 19:11:24 -0400
Subject: [PATCH] feat(wordpress): strip yoast_head fields from REST responses

Adds a pure trimResponseFields() helper applied inside makeWordPressRequest
right before the response is returned to the MCP client. By default it strips
the top-level yoast_head and yoast_head_json fields, which Yoast SEO adds to
every post/page response and which contribute ~10KB of pre-rendered schema
markup the LLM never needs.

The strip list is overridable via the MCP_WP_STRIP_FIELDS environment variable
(comma-separated). Set it to an empty string to disable trimming.

Only top-level fields are stripped; nested objects are left intact. Both
single-object responses and arrays of objects are handled. The escape hatch
on makeWordPressRequest (rawResponse: true) bypasses trimming.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
---
 README.md        | 19 +++++++++++++++++++
 src/wordpress.ts | 46 ++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 63 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index e9ae91d..41dd1f9 100644
--- a/README.md
+++ b/README.md
@@ -224,8 +224,27 @@ WORDPRESS_PASSWORD=wp_app_password
 
 # Optional: Custom SQL query endpoint (default: /mcp/v1/query)
 WORDPRESS_SQL_ENDPOINT=/mcp/v1/query
+
+# Optional: Comma-separated list of top-level fields to strip from
+# WordPress REST API responses before they are returned to the MCP
+# client. Defaults to "yoast_head,yoast_head_json" — read-only schema
+# markup that adds ~10KB to every response but is rarely useful to the
+# LLM. Set to an empty string to disable trimming.
+MCP_WP_STRIP_FIELDS=yoast_head,yoast_head_json
 ```
 
+## Response Trimming
+
+By default the server strips the top-level `yoast_head` and `yoast_head_json`
+fields from every WordPress REST API response before returning it to the MCP
+client. These fields contain Yoast SEO's pre-rendered schema markup, which the
+LLM almost never needs but pays tokens for on every request.
+
+- The trim applies to both single-object responses and arrays of objects.
+- Only **top-level** fields are stripped; nested objects are left untouched.
+- Override the list with the `MCP_WP_STRIP_FIELDS` environment variable
+  (comma-separated). Set it to an empty string to disable trimming entirely.
+
 ## Enabling SQL Query Tool (Optional)
 
 The `execute_sql_query` tool allows you to run read-only SQL queries against your WordPress database. This is an optional feature that requires adding a custom REST API endpoint to your WordPress site.
diff --git a/src/wordpress.ts b/src/wordpress.ts
index 92564bc..a8363f6 100644
--- a/src/wordpress.ts
+++ b/src/wordpress.ts
@@ -6,6 +6,46 @@ import { siteManager } from './config/site-manager.js';
 // Legacy global WordPress API client instance for backward compatibility
 let wpClient: AxiosInstance;
 
+const DEFAULT_STRIP_FIELDS = ['yoast_head', 'yoast_head_json'];
+
+/**
+ * Resolve the list of top-level fields to strip from WP REST responses.
+ * Reads MCP_WP_STRIP_FIELDS (comma-separated) and falls back to the default list.
+ * An empty string disables trimming.
+ */
+export function resolveStripFields(envValue?: string): string[] {
+  if (envValue === undefined) return DEFAULT_STRIP_FIELDS;
+  return envValue
+    .split(',')
+    .map(f => f.trim())
+    .filter(f => f.length > 0);
+}
+
+/**
+ * Pure function: return a shallow copy of `data` with `fields` removed at the
+ * top level. Arrays of objects are mapped; nested objects are left untouched.
+ * Non-object/non-array inputs (null, primitives) are returned as-is.
+ */
+export function trimResponseFields<T>(data: T, fields: string[]): T {
+  if (fields.length === 0) return data;
+  if (data === null || data === undefined) return data;
+
+  if (Array.isArray(data)) {
+    return data.map(item => trimResponseFields(item, fields)) as unknown as T;
+  }
+
+  if (typeof data === 'object') {
+    const fieldSet = new Set(fields);
+    const out: Record<string, unknown> = {};
+    for (const [key, value] of Object.entries(data as Record<string, unknown>)) {
+      if (!fieldSet.has(key)) out[key] = value;
+    }
+    return out as T;
+  }
+
+  return data;
+}
+
 /**
  * Initialize the WordPress API client with authentication
  * Now uses SiteManager for multi-site support
@@ -106,8 +146,10 @@ Status: ${response.status}
 Data: ${JSON.stringify(response.data, null, 2)}
 `;
     logToFile(responseLog, 'debug');
-    
-    return options?.rawResponse ? response : response.data;
+
+    if (options?.rawResponse) return response;
+    const stripFields = resolveStripFields(process.env.MCP_WP_STRIP_FIELDS);
+    return trimResponseFields(response.data, stripFields);
   } catch (error: any) {
     const errorLog = `
 ERROR: