254 Vanderbilt Avenue, Brooklyn, NY 11205
BBL 3020920060 (Borough 3, Block 2092, Lot 60) · BIN 3058583 · Last updated:
Also recorded in city data as: 254a78 Vanderbilt Ave
Summary · as of November 6, 2026
254 Vanderbilt Avenue (Brooklyn, NY 11205; tax lot BBL 3020920060) is an 8-unit walk-up apartment building (building class C4: old-law tenement), built around 1930, on a 3,760 sq ft lot zoned R6B. City tax records list the owner as DZL REALTY CORPORATION. The Department of Finance's final market value for tax year 2027 is $5,770,000. As of November 6, 2026, NYC Open Data shows one DOB job with a permit issued but no sign-off and one active DOB violation. There were four 311 requests in the past 12 months and no HPD complaints since 2019. (Source: NYC Open Data — DOB, HPD, OATH, DOF, DCP and ACRIS datasets — compiled by NYC Property Facts.)
- Owner of record
- DZL REALTY CORPORATION
- Building class
- C4 · Old-law tenement
- Year built · units
- 1930 · 8 res.
- Lot area · zoning
- 3,760 sq ft · R6B
- Market value (DOF)
- $5,770,000 FY2027
- Last priced deed
- —
- BBL
- 3020920060
- BIN
- 3058583
- 1Open DOB jobs (permit issued, no sign-off)
- 1Active DOB violations
- 0Active ECB violations
- 0Open HPD violations
- 0OATH tickets with unpaid balance
How to cite: NYC Property Facts, “254 Vanderbilt Avenue, Brooklyn, NY 11205 (BBL 3020920060)”, data as of 2026-11-06, https://nycpropertyfacts.com/ny/brooklyn/254-vanderbilt-avenue-3020920060. 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)
- DZL REALTY CORPORATIONThe owner name on the city’s tax records. It can lag behind recent sales and is often an LLC.
- Building class
- C4 – Old-law tenementThe 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
- 1930Often an estimate for older buildings.
- Floors
- 4
- Units
- 8 residential / 8 totalResidential units are apartments; total includes stores and offices.
- Buildings on lot
- 1
- Lot size
- 3,760 sq ft (40 ft × 94 ft)
- Building floor area
- 9,840 sq ft
- Zoning
- R6B, C2-4The 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)
- 2.62 built / 2.00 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).
- Identifiers
- BBL 3020920060 (Borough 3, Block 2092, Lot 60) · BIN 3058583BBL 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 2026-11-06; 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)
- $5,770,000The 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
- $2,596,500The portion of market value that taxes are calculated on (capped by law for small homes).
- Taxable value (final)
- $307,275Assessed value minus any exemptions.
- Tax class
- Tax class 2B – residential rental, 7–10 units
| Tax year | Roll | Market value | Assessed value | Tax class |
|---|---|---|---|---|
| 2027 | Final | $5,770,000 | $2,596,500 | 2B |
| 2026 | Final | $4,808,000 | $2,163,600 | 2B |
| 2025 | Final | $4,947,600 | $2,226,420 | 2B |
Source: DOF Property Valuation and Assessment Data — city dataset updated 2026-09-14; data as of 2026-11-06
Sales & deed history 11
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 |
|---|---|---|---|---|---|
| 2000-04-21 | DEED | $0 / not stated | Atkinson, Dora | Dzl Realty Corporation | FT_3210007396421 |
| 1987-03-26 | DEED | $0 / not stated | 254 Vanderbilt Ave Rlty | Atkinson, Dora | FT_3260001256926 |
| 1986-02-06 | DEED | $0 / not stated | Wen On Realty Corp | 254 Vanderbilt Ave Rlty | FT_3650001149865 |
| 1985-04-02 | DEED | $0 / not stated | Romano, Joseph F | Wen On Realty Corp | FT_3080001081508 |
| 1981-10-20 | DEED | $0 / not stated | Monaco Joseph; Monaco Ann | Romano Joseph F | BK_8130127201085 |
| 1975-07-22 | DEED | $0 / not stated | Vi Con Management Inc | Monaco Joseph; Monaco Ann | BK_7530079200803 |
| 1974-09-23 | DEED | $0 / not stated | Kane Thomas F; Graziadei John B | Vi Con Management Inc | BK_7430073700003 |
| 1973-12-24 | DEED | $0 / not stated | Hemlock Rlty Corp | Graziadei John B; Kane Thomas F | BK_7330068001028 |
| 1973-05-12 | DEED | $0 / not stated | Brandifino Frances; Serani Silvio | Hemlock Rlty Corp | BK_7330062901627 |
| 1972-07-18 | DEED | $0 / not stated | Serani Silvio; Brandifino Frances | Serani Silvio; Brandifino Frances | BK_7230056901077 |
| 1970-01-08 | DEED | $0 / not stated | Serani Maria | Serani Silvio; Serani Maria; Brandifino Frances | BK_7030038601489 |
Source: ACRIS Real Property Master — city dataset updated 2026-10-08; data as of 2026-11-06; ACRIS Real Property Legals — city dataset updated 2026-10-08; data as of 2026-11-06; ACRIS Real Property Parties — city dataset updated 2026-10-08; data as of 2026-11-06
DOB job filings 1 open of 3
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 ISSUED - PARTIAL JOB · 2008-01-25 | 310085074 BIS | A2 – Alteration with multiple work types (no change to use/occupancy) | 2008-01-24 | $15,000 |
| Not open SIGNED OFF · 2010-08-20 | 320035350 BIS | A2 – Alteration with multiple work types (no change to use/occupancy) | 2009-06-17 | $20,000 |
| Not open SIGNED OFF · 2006-12-18 | 302082396 BIS | A2 – Alteration with multiple work types (no change to use/occupancy) | 2006-02-15 | $80,000 |
Source: DOB NOW: Build – Job Application Filings — city dataset updated 2026-11-05; data as of 2026-11-06; DOB Job Application Filings (BIS) — city dataset updated 2026-11-05; data as of 2026-11-06
Work permits 5
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 |
|---|---|---|---|---|
| 2009-07-10 | 2009-11-26 | 320035350 BIS | Equipment work / Other / general construction | ISSUED (initial) |
| 2008-01-25 | 2008-09-17 | 310085074 BIS | Equipment work / Other / general construction | ISSUED (initial) |
| 2006-06-15 | 2007-06-16 | 302082396 BIS | Equipment work / Other / general construction | ISSUED (renewal) |
| 2006-05-22 | 2007-05-22 | 302082396 BIS | Plumbing / Plumbing | ISSUED (initial) |
| 2006-05-04 | 2006-06-16 | 302082396 BIS | Equipment work / Other / general construction | ISSUED (initial) |
Source: DOB NOW: Build – Approved Permits — city dataset updated 2026-11-05; data as of 2026-11-06; DOB Permit Issuance (BIS) — city dataset updated 2026-10-31; data as of 2026-10-31
DOB violations 1 active of 4
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 | 1993-08-16 | LL6291-LOCAL LAW 62/91 - BOILERS BOILER REQUIRED | V081693LL629139990 | |
| Resolved/dismissed V*-DOB VIOLATION - DISMISSED | 2009-12-31 | LBLVIO-LOW PRESSURE BOILER BOILER REQUIRED | V*123109LBLVIO12749 | |
| Resolved/dismissed V*-DOB VIOLATION - DISMISSED | 1997-09-16 | LL6291-LOCAL LAW 62/91 - BOILERS BOILER REQUIRED | V*091697LL6291224553 | |
| Resolved/dismissed V*-DOB VIOLATION - DISMISSED | 1995-08-29 | LL6291-LOCAL LAW 62/91 - BOILERS BOILER REQUIRED | V*082995LL629139008 |
Source: DOB Violations — city dataset updated 2026-11-05; data as of 2026-11-06
ECB violations (DOB) 0 active of 1
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: DISMISSED · Certification: N/A - DISMISSED | 2006-01-11 | Non-Hazardous | WORK W/O A PERMIT. WORK NOTED: REMOVED SHEETROCK COVERING FROM WALLS &CEILINGS REVEALING STRUCTURAL MEMBERS AND WOOD SHEATING. WORK LOCATION: APT # 3 THIRD FLR N SIDE. REMEDY: STOP ALL WORK. OBTAIN PERMIT. | $0 / $0 / $0 | 34507926H |
Source: DOB ECB Violations — city dataset updated 2026-11-05; data as of 2026-11-06
OATH tickets (all agencies) 0 unpaid of 17
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 # |
|---|---|---|---|---|---|---|
| No balance due PAID IN FULL | 2025-04-01 | Sanitation Others | IMPROPER DISPOSAL--BEDDING 1ST OCCURRENCE | DZL REALTY CORPORATION | $50 / $50 / $0 | 048986682J |
| No balance due Default PAID IN FULL · DEFAULTED | 2024-09-04 | Sanitation Others | IMPROPER DISPOSAL--BEDDING 1ST OCCURRENCE | DZL REALTY CORPORATION | $80 / $80 / $0 | 048430772J |
| No balance due HEARING COMPLETED · DISMISSED | 2024-07-11 | Police Department | OPERATION OF MOTORIZED SCOOTER WITHIN THE CITY OF NEW YORK | GUARCAX | $0 / $0 / $0 | 0214578376 |
| No balance due PAID IN FULL | 2021-12-15 | Sanitation Others | FAILURE TO CLEAN 18 INCHES INTO STREET | DZL REALTY CORPORATION | $50 / $50 / $0 | 047222236N |
| No balance due PAID IN FULL | 2020-12-27 | Sanitation Others | FAILURE TO CLEAN 18 INCHES INTO STREET | DZL REALTY CORPORATION | $100 / $100 / $0 | 047038438L |
| No balance due PAID IN FULL | 2020-02-14 | Sanitation Others | IMPROPER DISPOSAL BEDDING 1ST OFFENSE | DZL REALTY CORPORATION | $100 / $100 / $0 | 0210413363 |
| No balance due PAID IN FULL | 2020-01-16 | Dos - Enforcement Agents | UNCOVERED RECEPTACLES 1ST OFFENSE | DZL REALTY CORPORATION | $100 / $100 / $0 | 044365683Y |
| No balance due PAID IN FULL | 2018-11-03 | Dos - Enforcement Agents | RECYC PLACED FOR COLLECTION W NON-RECYC 1 TO 8 DWELLING UNITS | DZL REALTY CORPORATION | $25 / $25 / $0 | 042106824J |
| No balance due PAID IN FULL | 2018-09-01 | Sanitation Others | IMPROPER DISPOSAL BEDDING 1ST OFFENSE | DZL REALTY CORPORATION | $100 / $100 / $0 | 0205303515 |
| No balance due PAID IN FULL | 2017-02-17 | Sanitation Dept | FAILURE TO PROPERLY PUT RECYCS OUT FOR COLLECTION 1TO8DWELLING UNITS | DZL REALTY CORPORATION | $25 / $25 / — | 044940650X |
| No balance due Default PAID IN FULL · DEFAULT | 2016-10-21 | Sanitation Dept | FAILURE TO BUNDLE NEWSPAPES MAGAZINES CARDBOARD 1 TO 8 DWELLING UNITS | DZL REALTY CORPORATION | $25 / $25 / — | 044771940J |
| No balance due PAID IN FULL | 2016-05-03 | Sanitation Dept | RECYCLABLES PLACED FOR COLLECTION WITH NON-RECYC 9+ DWELLING UNITS | DZL REALTY CORPORATION | $100 / $100 / — | 042058951Z |
Showing 12 of 17 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
- 386024
- Last registered
- 2026-10-19
- Registration valid until
- 2027-09-01 CurrentRegistrations must be renewed every year.
| Role | Name | Company | Business city |
|---|---|---|---|
| Corporateowner | DZL REALTY CORP | Brooklyn, Ny | |
| Agent | Lisa Atkinson | DZL REALTY CORP | Brooklyn, Ny |
| Headofficer | Lisa Atkinson | Brooklyn, Ny | |
| Shareholder | Lisa Atkinson | Brooklyn, Ny | |
| Sitemanager | Martin Joseph |
Source: HPD Multiple Dwelling Registrations — city dataset updated 2026-11-04; data as of 2026-11-06; HPD Registration Contacts — city dataset updated 2026-11-04; data as of 2026-11-06
HPD housing-code violations 0 open of 18
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 · 2024-04-22 | A | 2024-04-12 | (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 · 2023-04-18 | A | 2023-03-27 | (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 · 2022-12-08 | I | 2022-11-04 | §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 · 2015-10-23 | I | 2015-10-14 | SECTION27-2107 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 P | |
| Closed Violation Closed · 2016-04-10 | B | 2009-10-01 | SECTION 27-2005 ADM CODE & 309 M/D LAW ABATE THE NUISANCE CONSISTING OF WINDOWS SEALED WITH WOOD & MASONRY BLOCK CELLAR THRU OUT. | |
| Closed Violation Closed · 2016-04-10 | B | 2009-10-01 | SECTION 27-2005, 2007 ADM CODE ARRANGE AND MAKE SELF-CLOSING THE DOORS PUBLIC HALL BULKHEAD DOOR TO ROOF | |
| Closed Violation Closed · 2016-04-10 | B | 2009-10-01 | SECTION 27-2005 ADM CODE PROPERLY REPAIR WITH SIMILAR MATERIAL THE BROKEN OR DEFECTIVE PLASTER CEILING CELLAR THRU OUT. | |
| Closed Violation Closed · 2016-04-10 | B | 2009-10-01 | 4R | SECTION 27-2045, 2046 ADM CODE PROVIDE AN APPROVED AND OPERATIONAL SMOKE DETECTING DEVICE, INSTALLED IN ACCORDANCE WITH DEPARTMENT OF BUILDINGS RULES AND REGULATIONS MISSING 4 STY APT 4R. , SECTION '' '' |
| Closed Violation Closed · 2016-04-10 | B | 2009-10-01 | 1R | SECTION 27-2005 ADM CODE PROPERLY REPAIR THE BROKEN OR DEFECTIVE MAKE OPERABLE TOP AND BOTTOM SASHES WINDOW WEST ROOM 1 STY APT 1R. , SECTION '' '' |
| Closed Violation Closed · 2016-07-10 | B | 2009-10-01 | 4L | SECTION 27-2005, 2007 ADM CODE FIRE EGRESS DEFECTIVE. REMOVE OBSTRUCTING BARS OR UNLAWFUL GATES FROM WINDOW TO FIRE ESCAPE OR PROVIDE APPROVED TYPE GATE 4 STY APT 4L. LOCATED AT APT 4L |
| Closed Violation Closed · 2016-04-10 | B | 2009-10-01 | SECTION 27-2005, 2007 ADM CODE AND DEPT. RULES AND REGULATIONS. REMOVE THE ENCUMBRANCE OBSTRUCTING EGRESS FROM FIRE ESCAPES ALL BALCONIES BLDG REAR. | |
| Closed Violation Closed · 2016-04-10 | B | 2009-10-01 | 1R | SECTION 27-2005 ADM CODE PROPERLY REPAIR THE BROKEN OR DEFECTIVE MAKE OPERABLE TOP SASH SOUTH WINDOW EAST ROOM 1 STY NORTH APT 1R. , SECTION '' '' |
| Closed Violation Closed · 2016-04-10 | B | 2009-10-01 | 1R | SECTION 27-2005 ADM CODE PROPERLY REPAIR THE BROKEN OR DEFECTIVE SPIRO FLEX SPRING TOP SASH WINDOW KITCHEN 1 STY NORTH APT 1R. , SECTION '' '' |
| Closed Violation Closed · 2016-04-10 | B | 2009-10-01 | SECTION 27-2005 ADM CODE PROPERLY REPAIR THE BROKEN OR DEFECTIVE PAVING CELLAR REAR | |
| Closed Violation Closed · 2016-04-10 | B | 2009-10-01 | SECTION 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 AT ENTRANCE BLDG FRONT. | |
| Closed Violation Closed · 2016-04-10 | B | 2009-10-01 | 1R | SECTION 27-2005 ADM CODE PROPERLY REPAIR THE BROKEN OR DEFECTIVE MECHANICAL SPRING BALANCES WINDOWS EAST ROOM AND KITCHEN 1 STY NORTH APT 1R , SECTION '' '' |
| Closed Violation Closed · 2016-04-10 | B | 2009-10-01 | SECTION 27-2005 ADM CODE & 309 M/D LAW ABATE THE NUISANCE CONSISTING OF EXPOSED ELECTRICAL WIRES CEILING AT METER BOXES CELLAR. | |
| Closed Violation Closed · 2016-04-10 | C | 2009-10-01 | SECTION 27-2033 ADM CODE PROVIDE READY ACCESS TO BUILDINGS HEATING SYSTEM BOILER ROOM DOOR LOCKED CELLAR. |
Source: HPD Housing Maintenance Code Violations — city dataset updated 2026-11-05; data as of 2026-11-06
HPD complaints 0
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.
No records found in this dataset for this lot.
Source: HPD Housing Maintenance Code Complaints and Problems — city dataset updated 2026-11-06; data as of 2026-11-06
311 requests (last 12 months) 4
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 |
|---|---|---|---|---|
| 2026-07-27 | DOT | Curb Condition – Broken Curb | Closed | 2026-08-14 |
| 2026-05-04 | NYPD | Illegal Parking – Double Parked Blocking Traffic | Closed | 2026-05-04 |
| 2025-11-15 | TLC | For Hire Vehicle Complaint – Driver Complaint - Non Passenger | Closed | 2026-04-06 |
| 2025-11-15 | NYPD | Illegal Parking – Blocked Bike Lane | Closed | 2025-11-15 |
Source: 311 Service Requests from 2020 to Present — city dataset updated 2026-11-06; data as of 2026-11-06
Nearby properties
More in Bedford-Stuyvesant (West): Open HPD violations · Active DOB violations · Active ECB violations · Open DOB jobs · Unpaid OATH tickets
On Vanderbilt Ave
- 257 Vanderbilt Avenue
- 258 Vanderbilt Avenue (12 open items)
- 259 Vanderbilt Avenue
- 246 Vanderbilt Avenue (five open items)
- 263 Vanderbilt Avenue
- 244 Vanderbilt Avenue (six open items)
- 265 Vanderbilt Avenue
- 240 Vanderbilt Avenue (one open item)
- 269 Vanderbilt Avenue (nine open items)
- 271 Vanderbilt Avenue
Same tax block (2092)
- 259 Clermont Avenue (six open items)
- 257 Clermont Avenue (42 open items)
- 255 Clermont Avenue (one open item)
- 253 Clermont Avenue
- 251 Clermont Avenue (one open item)
- 249 Clermont Avenue (27 open items)
- 247 Clermont Avenue (20 open items)
- 245 Clermont Avenue
- 243 Clermont Avenue
- 241 Clermont Avenue (18 open items)
All properties on Vanderbilt Ave, Brooklyn · All of Brooklyn 11205
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