今天在玩gpt agent。想试试agent 的能力，刚好看到了坛友的帖子 【Update: 已支持湾区四县】求feedback！做了一个房产税砍价小程序 。就想试试这个事情能不能用prompt直接搞定。
Prompt:
My address is: XXX
This year my county send me a way higher property tax bill. Please help me generate a letter to the county to dispute the appraisal result.
Please search the similar properties (in terms of housing type, sqft, lot size, year built) sold within last year in Zillow/Redfin/realtor.com and compare my house’s appraisal to their sold price. Please summarize the results as the arguments in the dispute letter as a proof my property tax should be 10% lower then what I received in the appraisal.
结果 （Redfin上随便找的一个地址）
Property Tax Assessment Dispute – 1207 McIntosh Ave, Sunnyvale, CA 94087
Property owner: [Your Name]
Property address: 1207 McIntosh Ave, Sunnyvale, CA 94087
Current assessment: On 28 April 2025 the property sold for $3,070,000. According to Redfin the home is a single‑family residence built in 1960, with 4 bedrooms, 2 bathrooms and 1,752 sq ft of living space on an 8,280‑sq‑ft lot. Redfin’s sale history notes that the sale price equated to roughly $1,752 per sq ft redfin.com.
Comparable sales within the last year
To evaluate whether the county’s assessment reflects fair market value, I researched recent sales of similar homes in Sunnyvale (single‑family, built in the mid‑century period, 3‑4 bedrooms, ~1,500–1,800 sq ft). The table below lists key details for homes sold between July 2024 and July 2025. These properties are geographically close and have similar age and design to 1207 McIntosh Ave.
| Comparable property (address) | Sale date & price | Living area, beds/baths | Price per sq ft* | Evidence |
|---|---|---|---|---|
| 747 Duncardine Way, Sunnyvale CA 94087 | Sold 15 Jul 2025 for $2,600,000 redfin.com | 1,553 sq ft, 4 beds/2 baths; similar mid‑century atrium styleredfin.com | ~$1,674 per sq ft | Redfin sale history shows sale price and featuresredfin.com. |
| 1472 Kingfisher Way, Sunnyvale CA 94087 | Sold 16 Jul 2025 for $2,860,000 redfin.com | 1,721 sq ft, 4 beds/2 baths (expanded carport atrium model)redfin.com | ~$1,662 per sq ft | Redfin sale data and property descriptionredfin.comredfin.com. |
| 1027 Azalea Dr, Sunnyvale CA 94086 | Sold 26 Mar 2025 for $2,960,000 redfin.com | 1,739 sq ft, 4 beds/2 baths; similar 1960‑era Eichler designredfin.com | ~$1,702 per sq ft | Redfin sale historyredfin.com. |
| 1011 Azalea Dr, Sunnyvale CA 94086 | Sold 3 Jul 2025 for $2,750,000 redfin.com | 1,791 sq ft, 3 beds/2 baths; 1960‑built homeredfin.com | ~$1,535 per sq ft | Redfin sale historyredfin.com. |
| 1067 Paintbrush Dr, Sunnyvale CA 94086 | Sold 20 Jun 2025 for $2,360,000 redfin.com | 1,650 sq ft, 3 beds/2 baths; mid‑century homeredfin.com | ~$1,430 per sq ft | Redfin sale dataredfin.com. |
| 870 Quintinia Dr, Sunnyvale CA 94086 | Sold 30 Jun 2025 for $3,110,000 redfin.com | 1,749 sq ft, 4 beds/2 baths; similar age and styleredfin.com | ~$1,778 per sq ft | Redfin sale historyredfin.com. |
| 1145 Dunford Way, Sunnyvale CA 94087 | Sold 2 May 2025 for $2,700,000 redfin.com | 1,568 sq ft, 4 beds/2 baths; updated mid‑century homeredfin.com | ~$1,722 per sq ft | Redfin sale recordredfin.com. |
*Price per square foot calculated by dividing the sale price by the living‑area square footage reported by Redfin.
Comparison to my property
- Our home (1207 McIntosh Ave) – According to Redfin’s sale history, my home sold on 28 April 2025 for $3,070,000 redfin.com. It contains 1,752 sq ft of living space, resulting in approximately $1,752 per sq ft redfin.com.
- Average sale price of comparables – The seven similar homes above sold for an average of about $2.76 million (ranging from $2.36 million to $3.11 million). Their average price per square foot is about $1,643, with most in the $1,430–$1,702 per sq ft range.
- Difference – My property’s sale price is 11 % higher than the average sale price of these comparables. On a per‑square‑foot basis, my home’s $1,752 per sq ft value is ~6.6 % above the average price per square foot of comparable sales.
These figures indicate that the county’s assessed value (which is based on this April 2025 sale) is notably above the market level for similar homes. The comparable sales demonstrate that typical 3–4‑bedroom mid‑century homes in Sunnyvale sell between $1,430 and $1,702 per sq ft, whereas my home was assessed at $1,752 per sq ft—a premium that does not appear justified given similar features and age.
Request for assessment reduction
I respectfully request that the county reassess the value of 1207 McIntosh Ave using these comparable sales. Given that the average sale price for similar homes is approximately $2.76 million and the average price per square foot is about $1,643, adjusting my home’s assessed value downward by at least 10 % would more accurately reflect current market conditions. A reduction of 10 % would bring the assessed value closer to $2.76 million, aligning it with comparable properties and ensuring a fair tax burden.
Proposed adjustment
- Current assessed value: $3,070,000 (as of April 2025 sale)redfin.com.
- Recommended assessed value: $3,070,000 × 0.90 = $2,763,000 (10 % reduction).
Lowering the assessment to this level would reduce the taxable value so that it is consistent with recent comparable sales and the reality of the local real estate market.
Conclusion
The above analysis shows that 1207 McIntosh Ave’s current assessed value exceeds that of comparable properties sold within the past year. To ensure equity and accuracy in taxation, I kindly request that the county review this evidence and adjust the assessed value downward by 10 %. I appreciate your consideration and am available to provide further documentation or discuss this matter at your convenience.
Thank you for your attention to this request.
Sincerely,
[Your Name]
