Add Plain English language instructions to all agent prompts

Instructs all five agents (legal, brand, channel best practices,
channel tech specs, lead) to prefer simple vocabulary over complex
alternatives (e.g. "add" over "incorporate", "about" over "regarding").
Also fixes "constitute" → "qualify as" in the legal agent prompt itself.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/app/agents/brand_agent.py

@@ -148,6 +148,7 @@ If the proof is nonsensical, not a marketing material, or cannot be analyzed, se
 - Example: "Logo placement incorrect (bottom-left) - move to top-right corner per guidelines"
 - IMPORTANT: Use British English spelling throughout all output (e.g. "authorised" not "authorized", "colour" not "color", "capitalise" not "capitalize", "organised" not "organized", "centre" not "center", "analysed" not "analyzed").
 - IMPORTANT: Never use the words "violation", "violates", or "violated" in your output. Use constructive alternatives such as "issue", "doesn't align with", "doesn't meet", or "conflicts with".
+- IMPORTANT: Use Plain English throughout. Choose simple, clear words over complex vocabulary. Prefer: "add" over "incorporate/integrate", "about" over "regarding", "qualifies as" over "constitutes", "use" over "utilise", "before" over "prior to", "to" over "in order to", "try" over "endeavour", "then" over "subsequently", "put in place" over "implement", "keep/contain" over "constrain", "standard interest rate" over "reversion rate". Avoid unnecessary jargon (e.g. use "exaggerated claim" instead of "puffery"). Feedback should be easy to understand for all users.
 """
 
         # Determine if revision fields should be included

backend/app/agents/channel_best_practices_agent.py

@@ -141,6 +141,7 @@ If the proof is nonsensical, not a marketing material, or cannot be analyzed, se
 - Example: "CTA placement below fold - move above fold for better visibility"
 - IMPORTANT: Use British English spelling throughout all output (e.g. "authorised" not "authorized", "colour" not "color", "capitalise" not "capitalize", "organised" not "organized", "centre" not "center", "analysed" not "analyzed").
 - IMPORTANT: Never use the words "violation", "violates", or "violated" in your output. Use constructive alternatives such as "issue", "doesn't align with", "doesn't meet", or "conflicts with".
+- IMPORTANT: Use Plain English throughout. Choose simple, clear words over complex vocabulary. Prefer: "add" over "incorporate/integrate", "about" over "regarding", "qualifies as" over "constitutes", "use" over "utilise", "before" over "prior to", "to" over "in order to", "try" over "endeavour", "then" over "subsequently", "put in place" over "implement", "keep/contain" over "constrain", "standard interest rate" over "reversion rate". Avoid unnecessary jargon (e.g. use "exaggerated claim" instead of "puffery"). Feedback should be easy to understand for all users.
 """
 
         # Determine if revision fields should be included

backend/app/agents/channel_tech_specs_agent.py

@@ -149,6 +149,7 @@ If the proof is nonsensical, not a marketing material, or cannot be analyzed, se
 - Example: "Image resolution 72dpi - increase to minimum 150dpi for print quality"
 - IMPORTANT: Use British English spelling throughout all output (e.g. "authorised" not "authorized", "colour" not "color", "capitalise" not "capitalize", "organised" not "organized", "centre" not "center", "analysed" not "analyzed").
 - IMPORTANT: Never use the words "violation", "violates", or "violated" in your output. Use constructive alternatives such as "issue", "doesn't align with", "doesn't meet", or "conflicts with".
+- IMPORTANT: Use Plain English throughout. Choose simple, clear words over complex vocabulary. Prefer: "add" over "incorporate/integrate", "about" over "regarding", "qualifies as" over "constitutes", "use" over "utilise", "before" over "prior to", "to" over "in order to", "try" over "endeavour", "then" over "subsequently", "put in place" over "implement", "keep/contain" over "constrain", "standard interest rate" over "reversion rate". Avoid unnecessary jargon (e.g. use "exaggerated claim" instead of "puffery"). Feedback should be easy to understand for all users.
 """
 
         # Determine if revision fields should be included

backend/app/agents/lead_agent.py

@@ -149,6 +149,7 @@ Your summary should:
 - For 'Passed': briefly note any amber items in 1-2 bullets
 - IMPORTANT: Use British English spelling throughout all output (e.g. "authorised" not "authorized", "colour" not "color", "capitalise" not "capitalize", "organised" not "organized", "centre" not "center", "analysed" not "analyzed").
 - IMPORTANT: Never use the words "violation", "violates", or "violated" in your output. Use constructive alternatives such as "issue", "doesn't align with", "doesn't meet", or "conflicts with".
+- IMPORTANT: Use Plain English throughout. Choose simple, clear words over complex vocabulary. Prefer: "add" over "incorporate/integrate", "about" over "regarding", "qualifies as" over "constitutes", "use" over "utilise", "before" over "prior to", "to" over "in order to", "try" over "endeavour", "then" over "subsequently", "put in place" over "implement", "keep/contain" over "constrain", "standard interest rate" over "reversion rate". Avoid unnecessary jargon (e.g. use "exaggerated claim" instead of "puffery"). Feedback should be easy to understand for all users.
 {revision_context}
 Here are the specialist reviews:
 {self._format_reviews(reviews)}

backend/app/agents/legal_agent.py

@@ -98,7 +98,7 @@ Use this metadata to focus your analysis on the specific legal requirements for
 Analyze the uploaded proof for legal compliance, checking:
 
 1. **Financial Promotion Detection**:
-   - Does this marketing material constitute a financial promotion?
+   - Does this marketing material qualify as a financial promotion?
    - A financial promotion is any communication that invites or induces a person to engage in investment activity or relates to financial products/services
    - Look for: interest rates, APR, loan offers, investment products, credit cards with financial terms, savings rates, etc.
    - If detected, set isFinancialPromotion to true and provide a clear reason
@@ -151,6 +151,7 @@ If the proof is nonsensical, not a marketing material, or cannot be analyzed, se
 - Example: "Missing APR disclaimer - add representative APR per FCA requirements"
 - IMPORTANT: Use British English spelling throughout all output (e.g. "authorised" not "authorized", "colour" not "color", "capitalise" not "capitalize", "organised" not "organized", "centre" not "center", "analysed" not "analyzed").
 - IMPORTANT: Never use the words "violation", "violates", or "violated" in your output. Use constructive alternatives such as "issue", "doesn't align with", "doesn't meet", or "conflicts with".
+- IMPORTANT: Use Plain English throughout. Choose simple, clear words over complex vocabulary. Prefer: "add" over "incorporate/integrate", "about" over "regarding", "qualifies as" over "constitutes", "use" over "utilise", "before" over "prior to", "to" over "in order to", "try" over "endeavour", "then" over "subsequently", "put in place" over "implement", "keep/contain" over "constrain", "standard interest rate" over "reversion rate". Avoid unnecessary jargon (e.g. use "exaggerated claim" instead of "puffery"). Feedback should be easy to understand for all users.
 """
 
         # Determine if revision fields should be included