Three GEO agencies have sent you proposals. All promise to make you visible on ChatGPT in 90 days. All have a "Generative Engine Optimization" page. None deliver the same thing.
Here are seven concrete criteria to distinguish a mature GEO agency from an SEO agency that's rebranded its offering. No jargon — just questions to ask and answers to expect.
1. Real LLM coverage
A serious GEO agency tracks the 7 surfaces that matter: ChatGPT, Perplexity, Gemini, Grok, Copilot, Google AI Mode and Google AI Overview. Coverage limited to ChatGPT alone covers 30-40% of the AI search market depending on your niche.
Question to ask: "Which LLMs do you track daily and with what tool?"
Acceptable answer: "We track all 7 LLMs on Mentionable, with daily scans and weekly reports."
Disqualifying answer: "We track ChatGPT manually, we add Perplexity on demand."
2. The pipeline methodology
GEO isn't a sequence of isolated audits. It's a monthly pipeline: continuous tracking, fan-out analysis, content execution, measurement, adjustment.
Ask to see their operational pipeline diagram. A serious agency has one. A rebranded SEO agency will talk about "methodology" without being able to describe it in steps.
Question to ask: "Describe the monthly cycle you operate for a typical client, step by step."
Acceptable answer: Week 1 = tracking and fan-out analysis, Week 2 = at-risk prompts identification + action plan, Weeks 3-4 = content execution + source optimization, end of month = report and prioritization.
Disqualifying answer: "We adapt to your needs."
3. Stack transparency
Ask which tracking platform the agency uses. Mentionable, Profound, Otterly, Peec — all are valid. None is a trade secret.
An agency that dodges this question or answers "we have our proprietary methods" has no stack. It improvises with manual screenshots.
Question to ask: "Which tracking platform do you use to measure citation share per LLM per prompt over 30 days?"
Acceptable answer: The name of a known platform + ability to show a dashboard screenshot.
Disqualifying answer: "We use internal tools." Or worse: "We check manually on ChatGPT."
4. Quantified case studies
A serious GEO case study contains four elements:
- Dated numbers measured on an identifiable tool
- LLMs explicitly named (not "on AI" but "on ChatGPT and Perplexity")
- Specific period (not "6 months" but "January to March 2026")
- Ability to speak with the referenced client if the engagement isn't confidential
Agencies that deliver PDFs with fuzzy charts and zero absolute numbers are lying or exaggerating. A real case study says: "Citation share on ChatGPT moved from 8% to 34% on 47 business-critical prompts over 90 days, measured on Mentionable."
Question to ask: "Can you show me a real (anonymized) client report from the last 30 days?"
5. Audit / monitoring / execution ratio
A well-balanced 12-month GEO engagement allocates:
- 15% of time to initial audit
- 35% to continuous monitoring and fan-out analysis
- 50% to content execution and source optimization
An agency proposing 80% audit / 20% execution delivers documentation, not results. An agency proposing 90% execution without continuous monitoring produces content blind.
Question to ask: "Over a 12-month engagement, how do hours split between audit, monitoring and execution?"
6. Realistic timelines
First measurable results (citation share evolution): 60-90 days. First business results (LLM referrer traffic, identified leads): 90-120 days.
Any agency promising results in under 60 days is overpromising. LLMs don't recrawl instantly, and citation changes take time to stabilize in rolling averages.
Question to ask: "After how many days do you typically observe a significant variation in citation share for a new client?"
Acceptable answer: "Between 60 and 90 days, sometimes more depending on the client's SEO maturity."
Disqualifying answer: "We've seen results in 30 days."
7. Absolute red flags
Five signals that should disqualify an agency immediately:
- Measurable results promised in under 30 days
- ChatGPT-only focus, without tracking Perplexity and Gemini
- Refusal to name the tracking platform used
- No quantified case studies on verifiable brands
- Pricing below $1,000/month with significant improvement promises
If an agency checks even two of these five signals, walk away.
A pre-vetted shortlist
If you want to skip the agency-by-agency filtering, Mentionable maintains a hand-picked directory of GEO agencies and consultants. Every listed agency has been verified against these seven criteria: LLM coverage, methodology, tracking stack, quantified case studies. No commission, no paid placement.
