677 Knickerbocker Avenue, Brooklyn, NY 11221
BBL 3033780004 (Borough 3, Block 3378, Lot 4) · BIN 3077318 · Last updated:
Summary · as of October 31, 2026
677 Knickerbocker Avenue (Brooklyn, NY 11221; tax lot BBL 3033780004) is a 3-unit walk-up apartment building (building class C0: three-family walk-up), built around 1910, on a 1,900 sq ft lot zoned R6. City tax records list the owner as HIGH FIVE POINTS MANAGEMENT INC.; the most recent deed with a stated price is dated November 25, 2020 at $1,300,000 (per ACRIS). The Department of Finance's final market value for tax year 2027 is $1,508,000. As of October 31, 2026, NYC Open Data shows 11 open HPD violations and one OATH ticket with an unpaid balance. There was one 311 request in the past 12 months and one HPD complaint since 2019. (Source: NYC Open Data — DOB, HPD, OATH, DOF, DCP and ACRIS datasets — compiled by NYC Property Facts.)
- Owner of record
- HIGH FIVE POINTS MANAGEMENT INC.
- Building class
- C0 · Three-family walk-up
- Year built · units
- 1910 · 3 res.
- Lot area · zoning
- 1,900 sq ft · R6
- Market value (DOF)
- $1,508,000 FY2027
- Last priced deed
- $1,300,000 · 2020-11-25
- BBL
- 3033780004
- BIN
- 3077318
- 0Open DOB jobs (permit issued, no sign-off)
- 0Active DOB violations
- 0Active ECB violations
- 11Open HPD violations
- 1OATH tickets with unpaid balance
How to cite: NYC Property Facts, “677 Knickerbocker Avenue, Brooklyn, NY 11221 (BBL 3033780004)”, data as of 2026-10-31, https://nycpropertyfacts.com/ny/brooklyn/677-knickerbocker-avenue-3033780004. Source: NYC Open Data.
Lot & building
Basic facts about the tax lot and building from the city’s PLUTO database.
- Owner (as listed by the city)
- HIGH FIVE POINTS MANAGEMENT INC.The owner name on the city’s tax records. It can lag behind recent sales and is often an LLC.
- Building class
- C0 – Three-family walk-upThe Department of Finance’s category for what kind of building this is.
- Land use
- Multi-family walk-up buildingsCity Planning’s broad category of how the lot is used.
- Year built
- 1910Often an estimate for older buildings.
- Floors
- 3
- Units
- 3 residential / 3 totalResidential units are apartments; total includes stores and offices.
- Buildings on lot
- 1
- Lot size
- 1,900 sq ft (20 ft × 95 ft)
- Building floor area
- 3,600 sq ft
- Zoning
- R6, C1-3The zoning district sets what can be built and used here. Residential district; the overlay (C1/C2…) allows local retail on residential blocks.
- Built vs. allowed density (FAR)
- 1.89 built / 2.43 max residentialFloor Area Ratio = building floor area ÷ lot area. If built FAR is below the maximum, zoning may allow more floor area (other rules apply).
- Identifiers
- BBL 3033780004 (Borough 3, Block 3378, Lot 4) · BIN 3077318BBL identifies the tax lot; BIN identifies each building (from DOB/HPD/footprint records).
Agency lookups: DOB BIS · ZoLa (zoning map) · ACRIS
Source: PLUTO (Dept. of City Planning) — city dataset updated 2026-08-24; data as of 2026-11-01; Building Footprints — city dataset updated 2026-10-25; data as of 2026-11-01
Tax assessment
How the Department of Finance values this lot for property tax.
- Market value (tax year 2027, final roll)
- $1,508,000The Department of Finance’s estimate of value for tax purposes. It is not an appraisal and is often far from the sale price.
- Assessed value
- $90,480The portion of market value that taxes are calculated on (capped by law for small homes).
- Taxable value (final)
- $25,580Assessed value minus any exemptions.
- Tax class
- Tax class 1 – 1–3 family homes (and some small mixed-use / vacant lots)
| Tax year | Roll | Market value | Assessed value | Tax class |
|---|---|---|---|---|
| 2027 | Final | $1,508,000 | $90,480 | 1 |
| 2026 | Final | $1,420,000 | $85,200 | 1 |
| 2025 | Final | $1,413,000 | $84,780 | 1 |
Source: DOF Property Valuation and Assessment Data — city dataset updated 2026-09-14; data as of 2026-11-01
Sales & deed history 6
Deeds recorded with the City Register (ACRIS). A deed transfers ownership. A $0 or very low price usually means a transfer between related parties, an estate, or a refinance-related transfer, not a market sale. This is not a title search; mortgages, liens and other documents are not shown.
| Date | Type | Price | Seller (grantor) | Buyer (grantee) | Doc ID |
|---|---|---|---|---|---|
| 2021-05-25 | DEED | $0 / not stated | Chan, Bo Chu | High Five Points Management Inc. | 2021072301311001 |
| 2020-11-25 | DEED | $1,300,000 | 677 Knickerbocker Ave Cg, Llc | Chan, Bo Chu | 2020120700426001 |
| 2019-01-30 | DEED | $0 / not stated | 677 Knickerbocker Ave Cg Llc | 677 Knickerbocker Ave Cg, Llc | 2019013000173001 |
| 2018-04-18 | DEED | $1,110,000 | Benjamin, Referee, Michael D | 677 Knickerbocker Ave Cg, Llc | 2018051700287001 |
| 1976-11-18 | DEED | $0 / not stated | Rumore Luigi; Rumore Lucia | Perez Jose; Perez Isabel | BK_7630088401924 |
| 1967-04-05 | DEED | $0 / not stated | Potestio Vincenza; Potestio Angelo | Rumore Luigi; Rumore Lucia | BK_6730039400048 |
Source: ACRIS Real Property Master — city dataset updated 2026-10-08; data as of 2026-11-01; ACRIS Real Property Legals — city dataset updated 2026-10-08; data as of 2026-11-01; ACRIS Real Property Parties — city dataset updated 2026-10-08; data as of 2026-11-01
DOB job filings 0 open of 5
A “job” is an application to the Department of Buildings to do construction work. A job marked Permitted, not signed off had a work permit issued but the city has no record of final sign-off (inspection/completion). Old jobs left in this state are common and appear in buyer and lender due diligence; the work may or may not have been done.
| Status | Job # | Type | Filed | Est. cost |
|---|---|---|---|---|
| Not open Approved · 2021-06-29 | B00448168-P1 DOB NOW | Alteration | 2021-06-28 | $22,500 |
| Not open LOC Issued · 2021-07-22 | B00448168-I1 DOB NOW | Alteration | 2021-01-06 | $22,500 |
| Not open SIGNED OFF · 2021-07-23 | 340800592 BIS | A2 – Alteration with multiple work types (no change to use/occupancy) | 2020-12-28 | $30,000 |
| Not open APPLICATION PROCESSED - ENTIRE · 2019-08-06 | 340691326 BIS | A3 – Minor alteration (one type of work) | 2019-08-06 | — |
| Not open PLAN EXAM - DISAPPROVED · 2019-06-27 | 321593478 BIS | A1 – Major alteration (changes use, egress or occupancy) | 2019-06-07 | $673,600 |
Source: DOB NOW: Build – Job Application Filings — city dataset updated 2026-10-31; data as of 2026-11-01; DOB Job Application Filings (BIS) — city dataset updated 2026-10-30; data as of 2026-10-31
Work permits 2
Individual permits issued under DOB jobs (one job can have several permits, e.g. plumbing and construction). Permit expiration alone does not mean the job was completed or signed off.
| Issued | Expires | Job # | Work | Permit status |
|---|---|---|---|---|
| 2021-01-22 | 2021-08-20 | B00448168-I1 DOB NOW | Plumbing PROPOSED INTERIOR RENOVATION ON CEL, 1ST THRU. 3RD FLOOR. PLUMBING & GAS WORKS AS PER PLAN. GENERAL CONSTRUCNTION WORK UNDER JOB #: 340800592. NO CHANGE IN USE, | Signed-off |
| 2021-01-12 | 2021-10-13 | 340800592 BIS | Equipment work / Other / general construction | ISSUED (initial) |
Source: DOB NOW: Build – Approved Permits — city dataset updated 2026-10-31; data as of 2026-11-01; DOB Permit Issuance (BIS) — city dataset updated 2026-10-31; data as of 2026-10-31
DOB violations 0 active of 0
Violations issued by the Department of Buildings for building-code or zoning conditions. Active means DOB has not recorded the violation as resolved or dismissed. Many active DOB violations are old (e.g. elevator or boiler inspection paperwork).
No records found in this dataset for this lot.
Source: DOB Violations — city dataset updated 2026-10-31; data as of 2026-11-01
ECB violations (DOB) 0 active of 0
DOB violations that go to a hearing at OATH (formerly the Environmental Control Board) and can carry fines. Active or Resolved follows the DOB violation status field. The hearing status is about the hearing and its penalty: written off means the city stopped collecting the fine, not that the condition was corrected. A balance due is a fine the city says is unpaid.
No records found in this dataset for this lot.
Source: DOB ECB Violations — city dataset updated 2026-10-31; data as of 2026-11-01
OATH tickets (all agencies) 1 unpaid of 25
Summonses heard at the Office of Administrative Trials and Hearings, from agencies like Sanitation, Buildings, Fire and Health, linked to this lot’s block and lot. Default means the respondent did not appear at the hearing, which typically results in the maximum penalty. Tickets may be issued to tenants or businesses at the address, not just the owner. DOB ECB tickets appear here too.
| Status | Date | Agency | Charge | Respondent | Imposed / paid / balance | Ticket # |
|---|---|---|---|---|---|---|
| Unpaid balance Default DOCKETED · DEFAULTED | 2025-05-16 | Sanitation Police | LITTERING 1ST OFFENSE | FIELDS | $112 / $0 / $112 | 048673119N |
| Hearing pending NEW ISSUANCE | 2026-10-17 | Dos - Enforcement Agents | DIRTY SIDEWALK | HIGH FIVE POINTS MANAGEMENT IN | $50 / $0 / $50 | 080168174Z |
| No balance due PAID IN FULL | 2026-07-23 | Dos - Enforcement Agents | FAILURE TO PROPERLY PUT RECYCS OUT FOR COLLECTION 1TO8DWELLING UNITS | HIGH FIVE POINTS MANAGEMENT IN | $25 / $25 / $0 | 049793976K |
| No balance due PAID IN FULL | 2026-06-25 | Sanitation Others | FAILURE TO CLEAN 18 INCHES INTO STREET | HIGH FIVE POINTS MANAGEMENT IN | $50 / $50 / $0 | 049885363X |
| No balance due HEARING COMPLETED · IN VIOLATION | 2026-03-16 | Sanitation Others | IMPROPER DISPOSAL--BEDDING 1ST OCCURRENCE | HIGH FIVE POINTS MANAGEMENT IN | $50 / $50 / $0 | 049537997R |
| No balance due HEARING COMPLETED · DISMISSED | 2026-03-16 | Dos - Enforcement Agents | IMPROPER DISPOSAL--BEDDING 1ST OCCURRENCE | HIGH FIVE POINTS MANAGEMENT IN | $0 / $0 / $0 | 049684487R |
| No balance due PAID IN FULL | 2025-10-02 | Sanitation Others | FAILURE TO CLEAN 18 INCHES INTO STREET | HIGH FIVE POINTS MANAGEMENT IN | $50 / $50 / $0 | 049430445Z |
| No balance due PAID IN FULL | 2024-09-14 | Sanitation Others | IMPROPER DISPOSAL--BEDDING 1ST OCCURRENCE | HIGH FIVE POINTS MANAGEMENT IN | $50 / $50 / $0 | 048584933N |
| No balance due PAID IN FULL | 2023-09-13 | Dos - Enforcement Agents | STORAGE OF RECEPTACLES PLACED OUT PRIOR TO 8PM WITHOUT A RECEPTACLE | HIGH FIVE POINTS MANAGEMENT IN | $50 / $50 / $0 | 048087888X |
| No balance due PAID IN FULL | 2023-06-24 | Sanitation Others | FAILURE TO CLEAN 18 INCHES INTO STREET | HIGH FIVE POINTS MANAGEMENT IN | $50 / $50 / $0 | 047904338M |
| No balance due PAID IN FULL | 2020-12-27 | Sanitation Recycling | IMPROPER DISPOSAL - 1ST OFFENSE | CARRASCO | $75 / $75 / $0 | 047095000H |
| No balance due PAID IN FULL | 2020-10-21 | Sanitation Others | STORAGE OF RECEPTACLES | 677 KNICKERBOCKER AVE CG LLC | $100 / $100 / $0 | 0212553184 |
Showing 12 of 25 records. The API and the source dataset have the full list.
Source: OATH Hearings Division Case Status — city dataset updated 2026-11-01; data as of 2026-11-01
HPD registration & contacts
Owners of most rental buildings must register with the Department of Housing Preservation and Development each year and list an owner and managing agent.
- HPD building ID
- 321382
- Last registered
- 2020-09-02
- Registration valid until
- 2021-09-01 ExpiredRegistrations must be renewed every year.
| Role | Name | Company | Business city |
|---|---|---|---|
| Officer | Jinkai Gao | Brooklyn, Ny | |
| Corporateowner | 677 KNICKERBOCKER AVE CG, LLC | Ridgewood, Ny | |
| Headofficer | Chunghei Cheung | Ridgewood, Ny | |
| Sitemanager | Colleen White | ||
| Agent | Jinkai Gao | Brooklyn, Ny |
Source: HPD Multiple Dwelling Registrations — city dataset updated 2026-10-28; data as of 2026-11-01; HPD Registration Contacts — city dataset updated 2026-10-28; data as of 2026-11-01
HPD housing-code violations 11 open of 78
Violations HPD inspectors issued for conditions in residential buildings (heat, leaks, mold, pests, lead paint, etc.). Class letters show how serious: Class A – non-hazardous (HPD gives 90 days to correct); Class B – hazardous (30 days to correct); Class C – immediately hazardous (24 hours to correct for most conditions); Class I – information / order (e.g. orders to register, lead or other administrative orders). Open means HPD has not recorded the condition as corrected.
| Status | Class | Issued | Apt | Condition |
|---|---|---|---|---|
| Open Nov Sent Out · 2026-05-05 | A | 2026-05-05 | (A) § HMC:FILE ANNUAL BEDBUG REPORT IN ACCORDANCE WITH HPD RULE AS DESCRIBED ON THE BACK OF THIS NOTICE OF VIOLATION OR AS DESCRIBED ON HPDS WEBSITE, WWW.NYC.GOV\HPD, SEARCH BED BUGS. | |
| Open Info Nov Sent Out · 2025-11-19 | I | 2025-11-19 | §27-2107 ADM CODE OWNER FAILED TO FILE A VALID REGISTRATION STATEMENT WITH THE DEPARTMENT AS REQUIRED BY ADM CODE §27-2097 AND IS THEREFORE SUBJECT TO CIVIL PENALTIES, PROHIBITED FROM CERTIFYING VIOLATIONS, AND DENIED THE RIGHT TO RECOVER POSSESSION OF PREMISE | |
| Open Nov Sent Out · 2025-06-10 | A | 2025-06-10 | (A) § HMC:FILE ANNUAL BEDBUG REPORT IN ACCORDANCE WITH HPD RULE AS DESCRIBED ON THE BACK OF THIS NOTICE OF VIOLATION OR AS DESCRIBED ON HPDS WEBSITE, WWW.NYC.GOV\HPD, SEARCH BED BUGS. | |
| Open Info Nov Sent Out · 2024-11-27 | I | 2024-11-27 | §27-2107 ADM CODE OWNER FAILED TO FILE A VALID REGISTRATION STATEMENT WITH THE DEPARTMENT AS REQUIRED BY ADM CODE §27-2097 AND IS THEREFORE SUBJECT TO CIVIL PENALTIES, PROHIBITED FROM CERTIFYING VIOLATIONS, AND DENIED THE RIGHT TO RECOVER POSSESSION OF PREMISE | |
| Open Nov Sent Out · 2024-04-10 | A | 2024-04-10 | (A) § HMC:FILE ANNUAL BEDBUG REPORT IN ACCORDANCE WITH HPD RULE AS DESCRIBED ON THE BACK OF THIS NOTICE OF VIOLATION OR AS DESCRIBED ON HPDS WEBSITE, WWW.NYC.GOV\HPD, SEARCH BED BUGS. | |
| Open Info Nov Sent Out · 2023-11-21 | I | 2023-11-21 | §27-2107 ADM CODE OWNER FAILED TO FILE A VALID REGISTRATION STATEMENT WITH THE DEPARTMENT AS REQUIRED BY ADM CODE §27-2097 AND IS THEREFORE SUBJECT TO CIVIL PENALTIES, PROHIBITED FROM CERTIFYING VIOLATIONS, AND DENIED THE RIGHT TO RECOVER POSSESSION OF PREMISE | |
| Open Nov Sent Out · 2023-03-23 | A | 2023-03-23 | (A) § HMC:FILE ANNUAL BEDBUG REPORT IN ACCORDANCE WITH HPD RULE AS DESCRIBED ON THE BACK OF THIS NOTICE OF VIOLATION OR AS DESCRIBED ON HPDS WEBSITE, WWW.NYC.GOV\HPD, SEARCH BED BUGS. | |
| Open Info Nov Sent Out · 2022-11-10 | I | 2022-11-10 | §27-2107 ADM CODE OWNER FAILED TO FILE A VALID REGISTRATION STATEMENT WITH THE DEPARTMENT AS REQUIRED BY ADM CODE §27-2097 AND IS THEREFORE SUBJECT TO CIVIL PENALTIES, PROHIBITED FROM CERTIFYING VIOLATIONS, AND DENIED THE RIGHT TO RECOVER POSSESSION OF PREMISE | |
| Open Nov Sent Out · 2022-02-25 | A | 2022-02-25 | (A) § HMC:FILE ANNUAL BEDBUG REPORT IN ACCORDANCE WITH HPD RULE AS DESCRIBED ON THE BACK OF THIS NOTICE OF VIOLATION OR AS DESCRIBED ON HPDS WEBSITE, WWW.NYC.GOV\HPD, SEARCH BED BUGS. | |
| Open Info Nov Sent Out · 2022-02-25 | I | 2022-02-25 | §27-2107 ADM CODE OWNER FAILED TO FILE A VALID REGISTRATION STATEMENT WITH THE DEPARTMENT AS REQUIRED BY ADM CODE §27-2097 AND IS THEREFORE SUBJECT TO CIVIL PENALTIES, PROHIBITED FROM CERTIFYING VIOLATIONS, AND DENIED THE RIGHT TO RECOVER POSSESSION OF PREMISE | |
| Open Nov Sent Out · 2021-04-09 | A | 2021-04-09 | (A) § HMC:FILE ANNUAL BEDBUG REPORT IN ACCORDANCE WITH HPD RULE AS DESCRIBED ON THE BACK OF THIS NOTICE OF VIOLATION OR AS DESCRIBED ON HPDS WEBSITE, WWW.NYC.GOV\HPD, SEARCH BED BUGS. | |
| Closed Violation Dismissed · 2020-11-04 | A | 2020-08-19 | § 27-2045 ADM CODE POST A PROPER NOTICE OF SMOKE DETECTOR REQUIREMENTS, IN A FORM APPROVED BY THE COMMISSIONER, AT OR NEAR THE MAIL BOX .. AT PUBLIC HALL, 1st STORY | |
| Closed Violation Dismissed · 2020-11-04 | B | 2020-08-19 | 3 | § 27-2005, 2007 ADM CODE REMOVE THE ILLEGAL FASTENING KEY OPERATED PADLOCK ON GATE TO FIRE ESCAPE IN THE KITCHEN LOCATED AT APT 3, 3rd STORY, 1st APARTMENT FROM NORTH AT EAST |
| Closed Violation Dismissed · 2020-11-04 | B | 2020-08-19 | 3 | § 27-2005 ADM CODE REPLACE WITH NEW THE BROKEN OR DEFECTIVE CERAMIC FLOOR TILES IN THE BATHROOM LOCATED AT APT 3, 3rd STORY |
| Closed Violation Dismissed · 2020-11-04 | C | 2020-08-19 | 3 | § 27-2026 ADM CODE REPAIR THE BROKEN OR DEFECTIVE CONNECTION WASTE LINE AT SINK IN THE BATHROOM LOCATED AT APT 3, 3rd STORY |
| Closed Violation Dismissed · 2020-11-04 | B | 2020-08-19 | 3 | § 27-2037, 2038 HMC: PROVIDE A SAFE AND ADEQUATE SUPPLY OF ELECTRIC SERVICE TO THE FIXTURES LIGHT FIXTURES AT CEILING IN THE BATHROOM LOCATED AT APT 3, 3rd STORY, 1st APARTMENT FROM WEST AT NORTH |
| Closed Violation Dismissed · 2020-11-04 | A | 2020-08-19 | § 27-2013 ADM CODE PAINT WITH LIGHT COLORED PAINT TO THE SATISFACTION OF THIS DEPARTMENT AT CEILING AT PUBLIC HALL, 3rd STORY | |
| Closed Violation Dismissed · 2020-11-04 | B | 2020-08-19 | § 27-2005 ADM CODE PROPERLY REPAIR THE BROKEN OR DEFECTIVE ELECTRICAL FIXTURE AT EAST WALL AT PUBLIC HALL, 3rd STORY | |
| Closed Violation Dismissed · 2020-11-04 | B | 2020-08-19 | 3 | § 27-2005 ADM CODE REPAIR THE BROKEN OR DEFECTIVE PLASTERED SURFACES AND PAINT IN A UNIFORM COLOR THE CEILING IN THE 4th ROOM FROM EAST LOCATED AT APT 3, 3rd STORY, 1st APARTMENT FROM NORTH AT EAST |
| Closed Violation Dismissed · 2020-11-04 | B | 2020-08-19 | § 27-2040 ADM CODE PROVIDE ADEQUATE LIGHTING AT OR NEAR THE OUTSIDE OF THE FRONT ENTRANCEWAY OF THE BUILDING AND KEEP SAME BURNING FROM SUNSET EVERY DAY TO SUNRISE ON THE DAY FOLLOWING 100 WATTS MINIMUM REQUIRED FIXTURE PRESENT LIGHT NOT ON |
Showing 20 of 78 records — open violations are listed first; the API lists every one. The API and the source dataset have the full list.
Source: HPD Housing Maintenance Code Violations — city dataset updated 2026-10-31; data as of 2026-11-01
HPD complaints 1
Complaints tenants or others made to HPD (usually via 311) about housing conditions, from 2019 onward. A complaint is not a violation; HPD may inspect and issue one.
| Received | Status | Apt | Problem(s) | Outcome |
|---|---|---|---|---|
| 2026-10-20 | CLOSE | BLDG | Heat/Hot Water – Entire Building | HPD responded to a complaint of no heat or hot water in the building. An occupant of the building confirmed heat and hot water had been restored when the Inspector attempted to conduct the inspection |
Source: HPD Housing Maintenance Code Complaints and Problems — city dataset updated 2026-11-01; data as of 2026-11-01
311 requests (last 12 months) 1
Recent 311 service requests the city geocoded to this lot: noise, illegal parking, heat, sanitation and more. Anyone can file them, so they describe activity at or near the address, not necessarily the building itself.
| Opened | Agency | Complaint | Status | Closed |
|---|---|---|---|---|
| 2026-10-20 | HPD | HEAT/HOT WATER – ENTIRE BUILDING | Closed | 2026-10-24 |
Source: 311 Service Requests from 2020 to Present — city dataset updated 2026-11-01; data as of 2026-11-01
Nearby properties
On Knickerbocker Ave
- 679 Knickerbocker Avenue (three open items)
- 675 Knickerbocker Avenue
- 673 Knickerbocker Avenue (one open item)
- 683 Knickerbocker Avenue (one open item)
- 671 Knickerbocker Avenue (nine open items)
- 685 Knickerbocker Avenue (16 open items)
- 667 Knickerbocker Avenue (three open items)
- 665 Knickerbocker Avenue (44 open items)
- 689 Knickerbocker Avenue (eight open items)
- 663 Knickerbocker Avenue (64 open items)
Same tax block (3378)
- 685 Knickerbocker Avenue (16 open items)
- 683 Knickerbocker Avenue (one open item)
- 679 Knickerbocker Avenue (three open items)
- 675 Knickerbocker Avenue
- 673 Knickerbocker Avenue (one open item)
- 671 Knickerbocker Avenue (nine open items)
- 667 Knickerbocker Avenue (three open items)
- 665 Knickerbocker Avenue (44 open items)
- 663 Knickerbocker Avenue (64 open items)
- 1398 Putnam Avenue (four open items)
All properties on Knickerbocker Ave, Brooklyn · All of Brooklyn 11221 (Bedford-Stuyvesant (East))
Open-item counts as of October 31, 2026; each section lists its own dataset date. Machine-readable: JSON API · Markdown · Plain text · API & MCP docs