83 2nd Avenue, Manhattan, NY 10003
BBL 1004600035 (Borough 1, Block 460, Lot 35) · BIN 1006591 · Last updated:
Summary · as of November 6, 2026
83 2nd Avenue (Manhattan, NY 10003; tax lot BBL 1004600035) is a 4-unit mixed-use building with apartments and ground-floor commercial space (building class S4: mixed-use: four-family home with one store or office), built around 1845, on a 1,600 sq ft lot zoned R7A. City tax records list the owner as COOPER SQUARE MUTUALHOUSING ASSOCIATION II ETC.. The Department of Finance's final market value for tax year 2027 is $5,844,000. As of November 6, 2026, NYC Open Data shows three DOB jobs with a permit issued but no sign-off and two active DOB violations. There were five 311 requests in the past 12 months and four HPD complaints since 2019. (Source: NYC Open Data — DOB, HPD, OATH, DOF, DCP and ACRIS datasets — compiled by NYC Property Facts.)
- Owner of record
- COOPER SQUARE MUTUALHOUSING ASSOCIATION II ETC.
- Building class
- S4 · Mixed-use: four-family home with one store or office
- Year built · units
- 1845 · 4 res.
- Lot area · zoning
- 1,600 sq ft · R7A
- Market value (DOF)
- $5,844,000 FY2027
- Last priced deed
- —
- BBL
- 1004600035
- BIN
- 1006591
- 3Open DOB jobs (permit issued, no sign-off)
- 2Active DOB violations
- 0Active ECB violations
- 0Open HPD violations
- 0OATH tickets with unpaid balance
How to cite: NYC Property Facts, “83 2nd Avenue, Manhattan, NY 10003 (BBL 1004600035)”, data as of 2026-11-06, https://nycpropertyfacts.com/ny/manhattan/83-2nd-avenue-1004600035. 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)
- COOPER SQUARE MUTUALHOUSING ASSOCIATION II ETC.The owner name on the city’s tax records. It can lag behind recent sales and is often an LLC.
- Building class
- S4 – Mixed-use: four-family home with one store or officeThe Department of Finance’s category for what kind of building this is.
- Land use
- Mixed residential & commercialCity Planning’s broad category of how the lot is used.
- Year built
- 1845Often an estimate for older buildings.
- Floors
- 5
- Units
- 4 residential / 5 totalResidential units are apartments; total includes stores and offices.
- Buildings on lot
- 1
- Lot size
- 1,600 sq ft (20 ft × 80 ft)
- Building floor area
- 7,885 sq ft (incl. 1,050 sq ft commercial)
- Zoning
- R7A, C2-5The 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)
- 4.93 built / 4.00 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).
- Historic district
- East Village / Lower East Side Historic DistrictExterior changes in a historic district need Landmarks Preservation Commission approval.
- Identifiers
- BBL 1004600035 (Borough 1, Block 460, Lot 35) · BIN 1006591BBL 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 2026-11-07; 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)
- $5,844,000The 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
- $2,629,800The portion of market value that taxes are calculated on (capped by law for small homes).
- Taxable value (final)
- $232,571Assessed value minus any exemptions.
- Tax class
- Tax class 2A – residential rental, 4–6 units
| Tax year | Roll | Market value | Assessed value | Tax class |
|---|---|---|---|---|
| 2027 | Final | $5,844,000 | $2,629,800 | 2A |
| 2026 | Final | $5,543,000 | $2,494,350 | 2A |
| 2025 | Final | $4,619,000 | $2,078,550 | 2A |
Source: DOF Property Valuation and Assessment Data — city dataset updated 2026-09-14; data as of 2026-11-07
Sales & deed history 4
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 |
|---|---|---|---|---|---|
| 1996-06-28 | DEED | $0 / not stated one deed covering 10 lots; price is for all of them | Nyc Hpd | Cooper Square Mutualhousing Association Ii Etc. | FT_1140005271314 |
| 1996-06-28 | DEED | $0 / not stated one deed covering 10 lots; price is for all of them | Cooper Square Mutualhousing Association Ii Etc. | Cooper Square Housing Development Fund Etc. | FT_1940005271294 |
| 1976-04-30 | DEED | $0 / not stated one deed covering 746 lots; price is for all of them | Finance Admins Cityny | City Of New York | FT_1300008560730 |
| 1969-09-12 | DEED | $0 / not stated | Goldin, Samuel J; Goldin, Florence W | Pete And Lou Realtycorp | FT_1460008464046 |
Source: ACRIS Real Property Master — city dataset updated 2026-10-08; data as of 2026-11-07; ACRIS Real Property Legals — city dataset updated 2026-10-08; data as of 2026-11-07; ACRIS Real Property Parties — city dataset updated 2026-10-08; data as of 2026-11-07
DOB job filings 3 open of 9
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 |
|---|---|---|---|---|
| Permitted, not signed off Permit Entire · 2026-10-02 | M01198444-I1 DOB NOW | Alteration | 2025-03-25 | $25,000 |
| Permitted, not signed off Permit Entire · 2025-05-08 | M01198409-I1 DOB NOW | Alteration | 2025-03-24 | $100,000 |
| Permitted, not signed off PERMIT ISSUED - ENTIRE JOB/WORK · 1991-02-27 | 100202068 BIS | A3 – Minor alteration (one type of work) | 1991-02-20 | — |
| Not open Approved · 2025-10-02 | M01198444-P2 DOB NOW | Alteration | 2025-10-01 | $25,000 |
| Not open Approved · 2025-04-24 | M01198444-P1 DOB NOW | Alteration | 2025-04-23 | $25,000 |
| Not open Approved · 2025-05-08 | M01198409-P1 DOB NOW | Alteration | 2025-04-23 | $100,000 |
| Not open SIGNED OFF · 2018-08-02 | 140701239 BIS | A3 – Minor alteration (one type of work) | 2017-09-29 | — |
| Not open SIGNED OFF · 2016-09-26 | 140538746 BIS | A2 – Alteration with multiple work types (no change to use/occupancy) | 2016-08-22 | $25,750 |
| Not open SIGNED OFF · 2000-11-27 | 101887736 BIS | A2 – Alteration with multiple work types (no change to use/occupancy) | 1998-06-25 | $60,000 |
Source: DOB NOW: Build – Job Application Filings — city dataset updated 2026-11-06; data as of 2026-11-07; DOB Job Application Filings (BIS) — city dataset updated 2026-11-05; data as of 2026-11-06
Work permits 11
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 |
|---|---|---|---|---|
| 2026-10-02 | 2027-02-01 | M01198444-I1 DOB NOW | Plumbing PLUMBING WORK IN CONJUNCTION WITH GC-M01198409-I1 | Permit Issued |
| 2026-09-01 | 2027-04-01 | M01198444-I1 DOB NOW | Plumbing PLUMBING WORK IN CONJUNCTION WITH GC-M01198409-I1 | Permit Issued |
| 2025-10-21 | 2026-10-21 | M01198444-I1 DOB NOW | Plumbing PLUMBING WORK IN CONJUNCTION WITH GC-M01198409-I1 | Permit Issued |
| 2025-04-03 | 2026-04-01 | M01198444-I1 DOB NOW | Plumbing PLUMBING WORK IN CONJUNCTION WITH GC-M01198409-I1 | Permit Issued |
| 2025-03-27 | 2026-03-27 | M01198409-I1 DOB NOW | General Construction INTERIOR RENOVATION FIT OUT FOR EXISTING COMMERCIAL SPACE AT 1ST FLR. NO CHANGE IN USE, EGRESS OR OCCUPANCY. | Permit Issued |
| 2025-03-27 | 2026-03-27 | M01198409-I1 DOB NOW | Mechanical Systems INTERIOR RENOVATION FIT OUT FOR EXISTING COMMERCIAL SPACE AT 1ST FLR. NO CHANGE IN USE, EGRESS OR OCCUPANCY. | Permit Issued |
| 2017-10-12 | 2018-10-12 | 140701239 BIS | Construction equipment (scaffold, fence, shed) / Construction equipment | ISSUED (initial) |
| 2016-08-23 | 2017-04-11 | 140538746 BIS | Equipment work / Other / general construction | ISSUED (initial) |
| 1999-05-11 | 2000-04-05 | 101887736 BIS | Equipment work / Other / general construction | ISSUED (renewal) |
| 1998-07-09 | 1999-04-05 | 101887736 BIS | Equipment work / Other / general construction | ISSUED (initial) |
| 1991-02-27 | 1991-12-31 | 100202068 BIS | Construction equipment (scaffold, fence, shed) / Construction equipment | ISSUED (initial) |
Source: DOB NOW: Build – Approved Permits — city dataset updated 2026-11-06; data as of 2026-11-07; DOB Permit Issuance (BIS) — city dataset updated 2026-11-07; data as of 2026-11-07
DOB violations 2 active of 9
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).
| Status | Issued | Type | Description | Number |
|---|---|---|---|---|
| Active V-DOB VIOLATION - ACTIVE | 2014-05-15 | LBLVIO-LOW PRESSURE BOILER BOILER REQUIRED | VIOLATION ISSUED FOR FAILURE TO FILE ANNUAL BOILER 2012 INSPECTION REPORT | V051514LBLVIO01451 |
| Active V-DOB VIOLATION - ACTIVE | 2011-12-13 | LBLVIO-LOW PRESSURE BOILER BOILER REQUIRED | VIOLATION ISSUED FOR FAILURE TO FILE ANNUAL BOILER 2010 INSPECTION REPORT | V121311LBLVIO00608 |
| Resolved/dismissed V*-DOB VIOLATION - DISMISSED | 2007-01-19 | LL6291-LOCAL LAW 62/91 - BOILERS BOILER REQUIRED | V*011907LL629103942 | |
| Resolved/dismissed V*-DOB VIOLATION - DISMISSED | 2005-01-31 | LL6291-LOCAL LAW 62/91 - BOILERS BOILER REQUIRED | V*013105LL629104343 | |
| Resolved/dismissed V*-DOB VIOLATION - DISMISSED | 2003-03-19 | LL6291-LOCAL LAW 62/91 - BOILERS BOILER REQUIRED | V*031903LL629101019 | |
| Resolved/dismissed V*-DOB VIOLATION - DISMISSED | 1999-03-16 | LL6291-LOCAL LAW 62/91 - BOILERS BOILER REQUIRED | V*031699LL629101076 | |
| Resolved/dismissed V*-DOB VIOLATION - DISMISSED | 1995-08-29 | LL6291-LOCAL LAW 62/91 - BOILERS BOILER REQUIRED | V*082995LL629106792 | |
| Resolved/dismissed V*-DOB VIOLATION - DISMISSED | 1994-03-18 | LL6291-LOCAL LAW 62/91 - BOILERS BOILER REQUIRED | V*031894LL629109061 | |
| Resolved/dismissed V*-DOB VIOLATION - DISMISSED | 1993-03-18 | LL6291-LOCAL LAW 62/91 - BOILERS BOILER REQUIRED | V*031893LL629109061 |
Source: DOB Violations — city dataset updated 2026-11-06; data as of 2026-11-07
ECB violations (DOB) 0 active of 2
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.
| Status | Issued | Severity | What it was for | Penalty / paid / balance | ECB # |
|---|---|---|---|---|---|
| Resolved Hearing: WRITTEN OFF · Certification: CERTIFICATE ACCEPTED Written off refers to the penalty, not the violation. | 1991-04-13 | Non-Hazardous | WORK WITHOUT A PERMIT. WORK NOTED:RENOVATING ABOVE PREMISES THROUGHOUT,WITHOUT A VARIANCE FOR WORKING ON WEEKENDS,REPAIRING FRONT 8FT FENCE WITH PLYWOOD. REMEDY:STOP ALL WORK-UNTIL A PROPER VARIANCE IS OBTAINED | $0 / $0 / $0 | 34045713K |
| Resolved Hearing: CURED/IN-VIO · Certification: CURE ACCEPTED | 1997-01-21 | Non-Hazardous | FAILURE TO MAINTAIN EXTERIOR BUILDING WALL NOTED(1) LOOSE BRICKWORK AND LOOSE MORTAR WORK IN APPROX 15'X10' SECTION OF NORTH REAR WALL AND 15' & 5' SECTION LOOSE & DEFECTIVE ON WESTSIDE (REAR) BETWEEN 3-5 FL LE | $0 / $0 / $0 | 34146544L |
Source: DOB ECB Violations — city dataset updated 2026-11-06; data as of 2026-11-07
OATH tickets (all agencies) 0 unpaid of 39
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 # |
|---|---|---|---|---|---|---|
| Hearing pending RESCHEDULED | 2026-08-19 | Pcs - Dohmh | FAIL TO ELIMINATE RODENT INFESTATION SHOWN BY ACTIVE RODENT SIGNS 1ST | $300 / $0 / $300 | 0803941977 | |
| No balance due PAID IN FULL | 2026-05-23 | Sanitation Others | FAILURE TO CLEAN 18 INCHES INTO STREET | COOPER SQUARE MUTUALHOUSING AS | $50 / $50 / $0 | 049783934N |
| No balance due PAID IN FULL · SETTL IN-VIO | 2025-10-07 | Sanitation Others | DIRTY SIDEWALK | COOPER SQUARE MUTUALHOUSING AS | $300 / $181 / $0 | 049360509H |
| No balance due PAID IN FULL | 2025-08-07 | Sanitation Others | IMPROPER RECEPTACLE FAILURE TO CONTAINERIZE - RESIDENTIAL 1ST | COOPER SQUARE MUTUALHOUSING AS | $50 / $50 / $0 | 049261462X |
| No balance due PAID IN FULL · SETTL IN-VIO | 2025-04-05 | Sanitation Others | IMPROPER RECEPTACLE FAILURE TO CONTAINERIZE - RESIDENTIAL 1ST | COOPER SQUARE MUTUALHOUSING AS | $300 / $189 / $0 | 049087431M |
| No balance due PAID IN FULL | 2025-02-06 | Sanitation Others | IMPROPER RECEPTACLE FAILURE TO CONTAINERIZE - RESIDENTIAL 1ST | COOPER SQUARE MUTUALHOUSING AS | $50 / $50 / $0 | 048906498R |
| No balance due PAID IN FULL | 2024-11-18 | Sanitation Others | DIRTY SIDEWALK | COOPER SQUARE MUTUALHOUSING AS | $50 / $50 / $0 | 048556158N |
| No balance due Default PAID IN FULL · DEFAULTED | 2023-09-16 | Dos - Enforcement Agents | FAILURE TO CLEAN 18 INCHES INTO STREET | COOPER SQUARE MUTUALHOUSING AS | $300 / $50 / $0 | 048041571Y |
| No balance due PAID IN FULL | 2020-03-16 | Sanitation Others | FAILURE TO CLEAN 18 INCHES INTO STREET | COOPER SQUARE MUTUAL HOUSING A | $100 / $100 / $0 | 0209159253 |
| No balance due PAID IN FULL | 2019-10-21 | Sanitation Others | IMPROPER DISPOSAL BEDDING 1ST OFFENSE | COOPER SQUARE MUTUAL HOUSING A | $100 / $100 / $0 | 0209154514 |
| No balance due PAID IN FULL | 2018-06-28 | Dos - Enforcement Agents | POSTING OF SIGN PERMIT, WASTE REMOVAL | DRESS SHOPPE | $100 / $100 / $0 | 043746248M |
| No balance due PAID IN FULL · SETTL IN-VIO | 2017-11-27 | Sanitation Others | IMPROPER DISPOSAL BEDDING 1ST OFFENSE | COOPER SQUARE MUTUAL HOUSE ASS | $300 / $202 / $0 | 0197229295 |
Showing 12 of 39 records. The API and the source dataset have the full list.
Source: OATH Hearings Division Case Status — city dataset updated 2026-11-06; data as of 2026-11-06
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
- 1564
- Last registered
- 2026-09-20
- Registration valid until
- 2027-09-01 CurrentRegistrations must be renewed every year.
| Role | Name | Company | Business city |
|---|---|---|---|
| Corporateowner | COOPER SQUARE MHA II HDFC | New York, Ny | |
| Officer | Sarah Perillo | New York, Ny | |
| Agent | David Powell | Cooper Square MHA Management | New York, Ny |
| Sitemanager | David Powell | ||
| Headofficer | David Powell | New York, Ny |
Source: HPD Multiple Dwelling Registrations — city dataset updated 2026-11-04; data as of 2026-11-07; HPD Registration Contacts — city dataset updated 2026-11-04; data as of 2026-11-07
HPD housing-code violations 0 open of 4
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 |
|---|---|---|---|---|
| Closed Violation Dismissed · 2024-07-15 | A | 2024-04-01 | (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 · 2023-11-30 | I | 2023-11-15 | §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 | |
| Closed Violation Dismissed · 2022-03-07 | A | 2022-02-15 | (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 · 2018-10-24 | B | 2018-07-24 | § 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 MINIMUM REQUIRED 100 WATTS (LIGHT FIXTURE PRESENT) AT FRONT AREAWAY, 1st ST |
Source: HPD Housing Maintenance Code Violations — city dataset updated 2026-11-06; data as of 2026-11-07
HPD complaints 4
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 |
|---|---|---|---|---|
| 2026-02-27 | CLOSE | 3A | Heat/Hot Water – Apartment Only | The Department of Housing Preservation and Development was not able to gain access to your apartment or others in the building to inspect for a lack of heat or hot water. The complaint has been closed |
| 2026-02-10 | CLOSE | 4A | Heat/Hot Water – Apartment Only | HPD called the telephone number on file for this complaint. Someone at that number indicated that the condition was corrected. The complaint has been closed. Please submit a new service request with |
| 2021-04-02 | CLOSE | BLDG | Heat/Hot Water – Entire Building | The Department of Housing Preservation and Development responded to a complaint of no heat or hot water and was advised by a tenant in the building that heat and hot water had been restored. If the co |
| 2020-07-11 | CLOSE | 4A | Plumbing – Water Supply | The Department of Housing Preservation and Development contacted an occupant of the apartment and verified that the following conditions were corrected. The complaint has been closed. If the condition |
Source: HPD Housing Maintenance Code Complaints and Problems — city dataset updated 2026-11-07; data as of 2026-11-07
311 requests (last 12 months) 5
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 |
|---|---|---|---|---|
| 2026-06-28 | DHS | Homeless Person Assistance – Non-Chronic | Closed | 2026-06-29 |
| 2026-02-27 | HPD | HEAT/HOT WATER – APARTMENT ONLY | Closed | 2026-03-02 |
| 2026-02-18 | NYPD | Noise - Residential – Loud Talking | Closed | 2026-02-18 |
| 2026-02-17 | NYPD | Noise - Residential – Loud Talking | Closed | 2026-02-17 |
| 2026-02-10 | HPD | HEAT/HOT WATER – APARTMENT ONLY | Closed | 2026-02-11 |
Source: 311 Service Requests from 2020 to Present — city dataset updated 2026-11-07; data as of 2026-11-07
Nearby properties
More in East Village: Open HPD violations · Active DOB violations · Active ECB violations · Open DOB jobs · Unpaid OATH tickets
On 2 Ave
- 82 2nd Avenue (28 open items)
- 84 2nd Avenue (four open items)
- 85 2nd Avenue (six open items)
- 81 2nd Avenue (six open items)
- 80 2nd Avenue (35 open items)
- 86 2nd Avenue (11 open items)
- 87 2nd Avenue (34 open items)
- 78 2nd Avenue (10 open items)
- 88 2nd Avenue (52 open items)
- 77 2nd Avenue (42 open items)
Same tax block (460)
- 1 Cooper Square (22 open items)
- 216 East 5th Street (23 open items)
- 218 East 5th Street (14 open items)
- 224 East 5th Street (two open items)
- 228 East 5th Street (two open items)
- 230 East 5th Street (two open items)
- 232 East 5th Street (three open items)
- 234 East 5th Street (one open item)
- 236 East 5th Street (14 open items)
- 242 East 5th Street (five open items)
Open-item counts as of November 6, 2026; each section lists its own dataset date. Machine-readable: JSON API · Markdown · Plain text · API & MCP docs