Is the dropped UnitWeight a Rhode Island sandbox bug?

No. The matrix was run on the sandbox on 2026-07-09, and a read-only pass over production packages in July 2026 agreed: the only weight-based production packages carrying a unit weight sat in Terpenes/Non Psychoactive Derivatives, the one concentrate category with RequiresUnitWeight true, and the weight was set at item creation.

Why does PUT /items/v2/ return 200 if it ignored my UnitWeight?

Because the call as a whole succeeded. The endpoint applies the fields the category allows and discards UnitWeight on a flag-false category; a Name change on the same call persisted. The body is {"Ids":[N],"Warnings":null} either way, so only a read-back shows the difference.

Which categories keep UnitWeight?

The ones whose row on GET /items/v2/categories carries RequiresUnitWeight: true. Of the 7 categories tested on 2026-07-09, 3 keep it (Shake/Trim, Infused Pre-Rolls, Pre-Packaged Bud) and 4 drop it (Bud/Flower, Kief, Concentrate, Concentrate (each)). Rhode Island served 21 categories on 2026-07-28; read the flag for the rest rather than inferring it from the name.

Can I make a bulk flower package sellable as fixed units by writing UnitWeight to METRC?

No. A package with a null unit weight is in a flag-false category by construction, and that is exactly where the write is dropped. Keep the per-unit weight on your own side and re-apply it after every sync, which is what SeedLink does; its packaging pre-flight has written nothing to METRC since 2026-08-23.

Why does my PUT fail with "Item N does not exist at the current Facility."?

Because the license on the call is not the facility that created the item. Items are facility-scoped: only the owner accepts PUT /items/v2/, and a non-owner answers HTTP 401, 404, or that 400. Read with GET /items/v2/{id}, which works across facilities, and write from the owning license.

What happens if UnitWeightUnitOfMeasure is not Grams?

A unit-of-measure mismatch on that field multiplied a unit weight by 1,000 in one live test in June 2026. SeedLink hardcodes the field to Grams on every create path rather than passing a unit through.

How do I create an item for a size I have never sold without guessing the category?

Copy it from a real item: reuse an existing Each item for the strain and size, else copy a same-size sibling’s exact name and ProductCategoryName, else render the brand’s own dominant name skeleton (at least 2 items must share it) at the new size with the most common flower Each category. On the sandbox in July 2026 this created a " - 7g" item at 7 Grams for a strain that had only 3.5 g items, and a re-run reused it.

Does the parent item’s UnitWeight matter when packaging?

Not in SeedLink’s packaging flow: nothing reads it, and every per-unit weight comes from SeedLink’s own row. What does matter is the source package’s unit of measure, read live from UnitOfMeasureName, because a draw in grams from an Each source is rejected by METRC.

Guides METRC field guides for Rhode Island

METRC item UnitWeight in Rhode Island: it persists only when the category has RequiresUnitWeight true, and the PUT returns 200 either way

On 2026-07-09, on the Rhode Island METRC sandbox, PUT /items/v2/ answered 200 {"Ids":[N],"Warnings":null} and silently dropped UnitWeight on all 4 tested categories whose RequiresUnitWeight flag is false (Bud/Flower, Kief, Concentrate, Concentrate (each)), and persisted it on all 3 tested categories whose flag is true (Shake/Trim, Infused Pre-Rolls, Pre-Packaged Bud). The flag is a per-category boolean on GET /items/v2/categories, the PUT is otherwise live (a Name change on the same call persists), and production agreed in July 2026. This is neither a sandbox artifact nor a bug; it is how the category flag works.

Observed: August 23, 2026
Revised: September 20, 2026
Environment: Rhode Island production and sandbox

What this page is

This page records what SeedLink’s METRC integration observed on the Rhode Island API when it wrote item unit weights and read them back, dated, with the call that produced each observation. It is not METRC documentation and it is not regulatory guidance: it describes how the item endpoints behaved for licensed Rhode Island cultivators on the dates given.

It is not a guide to choosing a unit of measure for a product, and the matrix here is not the whole category table: it covers the 7 categories that were tested, out of the 21 Rhode Island served on 2026-07-28. Other states run their own METRC instances and can differ on every point below.

Where SeedLink’s own handling is described (a per-unit weight kept on its side of the integration, the item-creation cascade), it is described as what the code does today, not as the only correct design.

How every number on this site is observed, dated and bounded is on the methodology page, which also lists what SeedLink does not publish.

The flag lives on the categories endpoint, not on the item

GET /items/v2/categories?licenseNumber=... returns one row per item category the state serves, and each row carries a boolean named RequiresUnitWeight. That boolean, not anything on the item itself, decides whether the UnitWeight you send on POST /items/v2 or PUT /items/v2/ is kept. The same rows carry other per-category flags (RequiresStrain among them; see the strain guide linked below).

On 2026-07-09 SeedLink live-tested 7 categories on the Rhode Island sandbox at one cultivator facility, 3 with the flag true and 4 with it false, sending UnitWeight on both the create and the update call and reading each item back afterwards.

RequiresUnitWeight and what the item endpoints did with UnitWeight, Rhode Island sandbox, one cultivator facility, 2026-07-09
Category	`RequiresUnitWeight`	What `PUT /items/v2/` and `POST /items/v2` did with `UnitWeight`
Shake/Trim	true	Persisted; `POST` returned HTTP 400 without it
Infused Pre-Rolls	true	Persisted; `POST` returned HTTP 400 without it
Pre-Packaged Bud	true	Persisted; `POST` returned HTTP 400 without it
Bud/Flower	false	HTTP 200, silently dropped
Kief	false	HTTP 200, silently dropped
Concentrate	false	HTTP 200, silently dropped
Concentrate (each)	false	HTTP 200, silently dropped

Rhode Island served 21 item categories when SeedLink read the endpoint live at one production cultivator facility on 2026-07-28. The 7 above are the ones the matrix exercised; the flag on the other categories is read from the same endpoint, never inferred from a category name.

The 200 is real, and it is not a sandbox bug

The update call answers 200 {"Ids":[N],"Warnings":null} in both halves of the matrix: no warning, no partial-success code, nothing in the body that says a field was ignored.

The call is not a no-op either. On the same PUT /items/v2/ that dropped UnitWeight on a flag-false category, a Name change persisted. The endpoint is live: it applies the fields the category allows, discards the one it does not, and reports success for the call as a whole.

SeedLink’s own field guide once recorded this as a Rhode Island sandbox no-op bug. It is neither sandbox-specific nor a bug. A read-only pass over production packages in July 2026 found that the only weight-based production packages carrying a unit weight belonged to the one concentrate category that carries the flag, Terpenes/Non Psychoactive Derivatives, and that the weight had been set at item creation. Production and sandbox agree on the rule.

A 200 on PUT /items/v2/ means the call was accepted, not that every field in it was stored. Read the item back before believing a unit weight.

A null unit weight can never be repaired by writing it back

The consequence follows from the flag alone, in three steps, and it leaves no package for which writing UnitWeight back to METRC is both needed and effective.

Flag true: POST /items/v2 returns HTTP 400 without UnitWeight, so the value is required at creation, never null, and never needs writing.
Flag false: UnitWeight is dropped on every write, so writing it changes nothing.
A package with a null unit weight is in a flag-false category by construction, so the write that would fix it is the write that is dropped.

SeedLink therefore stores the per-unit weight on its own side for a mass package the cultivator sells as fixed units, and re-applies it to the row’s weight and unit count on every sync. METRC keeps the package in grams; the fixed-unit view is re-derived on each pass rather than read back.

SeedLink’s packaging pre-flight used to send the write anyway; since 2026-08-23 it writes nothing to METRC. The write only ran for packages whose unit weight was null, which are flag-false by construction, so it was dropped; on the flag-true categories where it would have persisted, the value was never null, so it was never sent; and nothing in the packaging flow reads the parent item’s UnitWeight, since every per-unit weight comes from SeedLink’s own row. Measured on a replica of one production catalog before the change, it logged "updated" and then "did not persist" on every run. Its only possible effect was to abort a run on a 400 or 401 over a value nothing read.

Writes to the item endpoints and what each one persisted, Rhode Island sandbox, 2026-07-09 unless noted
Write	`RequiresUnitWeight`	Status	What persisted
`POST /items/v2` without `UnitWeight`	true	HTTP 400	Nothing; the item is not created
`POST /items/v2` with `UnitWeight`	true	Item created; code not recorded	The item and its `UnitWeight` (the 7 g item in the cascade test, July 2026)
`PUT /items/v2/` with `UnitWeight`	true	HTTP 200	`UnitWeight`
`PUT /items/v2/` with `UnitWeight`	false	HTTP 200, body `{"Ids":[N],"Warnings":null}`	Every field except `UnitWeight`
`PUT /items/v2/` with a `Name` change	false	HTTP 200	The new `Name`, on the same call that dropped `UnitWeight`
`PUT /items/v2/` from a facility that does not own the item	either	HTTP 401, 404, or 400 with `Item N does not exist at the current Facility.`	Nothing
The SeedLink pre-flight `UnitWeight` write, before 2026-08-23	false by construction	HTTP 200	Nothing: logged "updated", then "did not persist", every run on a production replica

Items belong to the facility that created them

An item is owned by the facility that created it, and a package transferred in from another facility (a lab’s returned packages, for example) still references the original item by Item.Id. GET /items/v2/{id} treats licenseNumber as optional and returns the item across facilities. PUT /items/v2/ does require licenseNumber, and only the owning facility accepts the call.

A facility that does not own the item answers in one of three shapes: HTTP 401, HTTP 404, or HTTP 400 with the body Item N does not exist at the current Facility. All three mean the same thing: try the next facility the credential can see. The 400 shape was observed live on the Rhode Island sandbox on 2026-07-09, and it mattered. SeedLink’s facility walk had retried only on 401 and 404 and aborted on the 400, so an item genuinely owned by another facility never reached its owner. The walk now treats all three as a wrong facility and continues down /facilities/v2/. The general lesson: a 400 on this endpoint is not a validation failure until its body has been read.

How to mint an item without guessing a category

Every retail size is a distinct METRC item that has to exist before a package can be created against it, and new strains and new sizes arrive constantly. The wrong shortcut is to guess. The ItemCategory prints on the physical sticker, and METRC locks the sticker’s item name 24 hours after packaging, so a guessed category is a re-label. SeedLink resolves the item through a tightening cascade, and every create is confirmed by the cultivator in a modal before the irreversible call.

The item-creation cascade: what each step reads and what it guarantees
Step	What it reads	What it guarantees
Reuse	An existing `Each` item matching the strain and the size	No create at all; a re-run finds the same item
Same-size sibling	A same-size sibling item’s exact name and its real `ProductCategoryName`	The category is copied from a real item, never guessed; the name follows the sibling with the strain swapped
Learned template	The dominant "{strain} {size}" name skeleton in the brand’s own item history, with at least 2 items sharing it	A size the brand has never shipped gets a name in the brand’s own convention, and the brand’s most common flower `Each` category
Plain or bulk	No `Each` items at all, or no skeleton shared by 2 items	A plain "{strain} {size}" name, or the line ships as bulk grams

Live-verified on the Rhode Island sandbox in July 2026: a 7 g quarter of a strain that had only 3.5 g items had no same-size sibling, so the learned template created a "<strain> - 7g" item as Each, Pre-Packaged Bud, UnitWeight 7 Grams. A second run reused that item rather than minting another. Pre-Packaged Bud is a flag-true category, so the unit weight was required at creation and persisted.

UnitWeightUnitOfMeasure is hardcoded to Grams on every create path. A unit-of-measure mismatch on that field multiplied a weight by 1,000 in one live test in June 2026, so the unit is pinned rather than passed through.
ItemCategory is always copied from a real sibling item or from the brand’s most common flower Each category, never inferred from a keyword, because it prints on the sticker.
Every create path finds by exact name first, so a retry reuses and never double-mints.
Auto-creation is scoped to flower with a known strain; concentrates carry a null StrainName and are reuse-only.

The unit weight is not the draw

Two different quantities are easy to conflate. UnitWeight describes one unit of the item. The ingredient draw on POST /packages/v2/ describes how much of the source package moves into the new one, and it has to be expressed in the source package’s own unit of measure, read live from its UnitOfMeasureName rather than assumed from the category. METRC rejects a draw in grams from an Each source. A mass source gives up total grams; a count source gives up base units, the package quantity times the pack count.

A multi-pack is a distinct item from its single, not a quantity of it: same category and strain, still Each, with UnitWeight equal to the pack count times the per-unit grams and a "<single> - N pack" name. As a worked example, a 3-pack of 1.2 g units carries UnitWeight 3.6. The shape matches what one Rhode Island production facility already held for the multi-packs it makes by hand. The multi-pack package is drawn from the singles package as base units, arithmetic METRC does not do for you.

The category matters here for a second reason: in SeedLink the mapped master category drives the unit-of-measure choice for packaging, so a mis-mapped category does not mislabel a menu, it blocks packaging with an error naming the category. A blocked run costs a support message; a wrong category on a sticker costs a re-label.

Check it yourself: one read answers it, one write confirms it

The flag is readable with one GET and no writes. The confirmation needs a write, so do it on a sandbox item you own and send only the field you are testing, because the PUT is live.

GET https://api-ri.metrc.com/items/v2/categories?licenseNumber=<your license>
Authorization: Basic <base64 of VENDOR_KEY:USER_KEY>

for each row in the response:
  note Name and RequiresUnitWeight

then, for one item you own in a category whose flag is false:
  GET  /items/v2/<item id>                        record UnitWeight
  PUT  /items/v2/?licenseNumber=<your license>    the item, UnitWeight set, UnitWeightUnitOfMeasure "Grams"
  GET  /items/v2/<item id>                        compare UnitWeight to what you sent

If the read-back matches what you sent, the category keeps unit weights. If it comes back unchanged beside a 200, you have reproduced this page, and the value belongs on your side of the integration.

Questions

Is the dropped UnitWeight a Rhode Island sandbox bug?: No. The matrix was run on the sandbox on 2026-07-09, and a read-only pass over production packages in July 2026 agreed: the only weight-based production packages carrying a unit weight sat in Terpenes/Non Psychoactive Derivatives, the one concentrate category with RequiresUnitWeight true, and the weight was set at item creation.
Why does PUT /items/v2/ return 200 if it ignored my UnitWeight?: Because the call as a whole succeeded. The endpoint applies the fields the category allows and discards UnitWeight on a flag-false category; a Name change on the same call persisted. The body is {"Ids":[N],"Warnings":null} either way, so only a read-back shows the difference.
Which categories keep UnitWeight?: The ones whose row on GET /items/v2/categories carries RequiresUnitWeight: true. Of the 7 categories tested on 2026-07-09, 3 keep it (Shake/Trim, Infused Pre-Rolls, Pre-Packaged Bud) and 4 drop it (Bud/Flower, Kief, Concentrate, Concentrate (each)). Rhode Island served 21 categories on 2026-07-28; read the flag for the rest rather than inferring it from the name.
Can I make a bulk flower package sellable as fixed units by writing UnitWeight to METRC?: No. A package with a null unit weight is in a flag-false category by construction, and that is exactly where the write is dropped. Keep the per-unit weight on your own side and re-apply it after every sync, which is what SeedLink does; its packaging pre-flight has written nothing to METRC since 2026-08-23.
Why does my PUT fail with "Item N does not exist at the current Facility."?: Because the license on the call is not the facility that created the item. Items are facility-scoped: only the owner accepts PUT /items/v2/, and a non-owner answers HTTP 401, 404, or that 400. Read with GET /items/v2/{id}, which works across facilities, and write from the owning license.
What happens if UnitWeightUnitOfMeasure is not Grams?: A unit-of-measure mismatch on that field multiplied a unit weight by 1,000 in one live test in June 2026. SeedLink hardcodes the field to Grams on every create path rather than passing a unit through.
How do I create an item for a size I have never sold without guessing the category?: Copy it from a real item: reuse an existing Each item for the strain and size, else copy a same-size sibling’s exact name and ProductCategoryName, else render the brand’s own dominant name skeleton (at least 2 items must share it) at the new size with the most common flower Each category. On the sandbox in July 2026 this created a "<strain> - 7g" item at 7 Grams for a strain that had only 3.5 g items, and a re-run reused it.
Does the parent item’s UnitWeight matter when packaging?: Not in SeedLink’s packaging flow: nothing reads it, and every per-unit weight comes from SeedLink’s own row. What does matter is the source package’s unit of measure, read live from UnitOfMeasureName, because a draw in grams from an Each source is rejected by METRC.

Sources and how to cite this page

Live-tested matrix of PUT /items/v2/ and POST /items/v2 against the RequiresUnitWeight flag on GET /items/v2/categories, Rhode Island sandbox, one cultivator facility, 2026-07-09; the wrong-facility 400 body observed the same day.
Read-only read of weight-based active packages carrying a unit weight at Rhode Island production cultivator facilities, July 2026.
GET /items/v2/categories at one Rhode Island production cultivator facility, read live, 2026-07-28; the table is pinned by a test in the SeedLink repository, so the page cannot drift from the code.
SeedLink item-creation cascade and multi-pack item flow, live-verified on the Rhode Island sandbox, July 2026; the packaging pre-flight change of 2026-08-23; the unit-of-measure guard from a live test in June 2026.
SeedLink METRC field guide (docs/METRC.md), sections UnitWeight persists ONLY for RequiresUnitWeight=true categories, Items Are Facility-Scoped, Tier A Category-Aware UoM, and Categories.

SeedLink, "METRC item UnitWeight in Rhode Island: it persists only when the category has RequiresUnitWeight true, and the PUT returns 200 either way", observed 2026-08-23, revised 2026-09-20, https://www.seedlink.net/guides/metrc/unit-weight-requires-unit-weight

Every figure above carries the date it was observed and the environment it was observed in. A count belongs to one facility on one day; the field names, orderings and error messages are the durable part.

Machine-readable copy of this page, with the same facts, dates and sources: /guides/metrc/unit-weight-requires-unit-weight/data.json

Guides METRC field guides for Rhode Island

METRC item UnitWeight in Rhode Island: it persists only when the category has RequiresUnitWeight true, and the PUT returns 200 either way

Observed: August 23, 2026
Revised: September 20, 2026
Environment: Rhode Island production and sandbox

What this page is

How every number on this site is observed, dated and bounded is on the methodology page, which also lists what SeedLink does not publish.

The flag lives on the categories endpoint, not on the item

RequiresUnitWeight and what the item endpoints did with UnitWeight, Rhode Island sandbox, one cultivator facility, 2026-07-09
Category	`RequiresUnitWeight`	What `PUT /items/v2/` and `POST /items/v2` did with `UnitWeight`
Shake/Trim	true	Persisted; `POST` returned HTTP 400 without it
Infused Pre-Rolls	true	Persisted; `POST` returned HTTP 400 without it
Pre-Packaged Bud	true	Persisted; `POST` returned HTTP 400 without it
Bud/Flower	false	HTTP 200, silently dropped
Kief	false	HTTP 200, silently dropped
Concentrate	false	HTTP 200, silently dropped
Concentrate (each)	false	HTTP 200, silently dropped

The 200 is real, and it is not a sandbox bug

The update call answers 200 {"Ids":[N],"Warnings":null} in both halves of the matrix: no warning, no partial-success code, nothing in the body that says a field was ignored.

A 200 on PUT /items/v2/ means the call was accepted, not that every field in it was stored. Read the item back before believing a unit weight.

A null unit weight can never be repaired by writing it back

The consequence follows from the flag alone, in three steps, and it leaves no package for which writing UnitWeight back to METRC is both needed and effective.

Flag true: POST /items/v2 returns HTTP 400 without UnitWeight, so the value is required at creation, never null, and never needs writing.
Flag false: UnitWeight is dropped on every write, so writing it changes nothing.
A package with a null unit weight is in a flag-false category by construction, so the write that would fix it is the write that is dropped.

Writes to the item endpoints and what each one persisted, Rhode Island sandbox, 2026-07-09 unless noted
Write	`RequiresUnitWeight`	Status	What persisted
`POST /items/v2` without `UnitWeight`	true	HTTP 400	Nothing; the item is not created
`POST /items/v2` with `UnitWeight`	true	Item created; code not recorded	The item and its `UnitWeight` (the 7 g item in the cascade test, July 2026)
`PUT /items/v2/` with `UnitWeight`	true	HTTP 200	`UnitWeight`
`PUT /items/v2/` with `UnitWeight`	false	HTTP 200, body `{"Ids":[N],"Warnings":null}`	Every field except `UnitWeight`
`PUT /items/v2/` with a `Name` change	false	HTTP 200	The new `Name`, on the same call that dropped `UnitWeight`
`PUT /items/v2/` from a facility that does not own the item	either	HTTP 401, 404, or 400 with `Item N does not exist at the current Facility.`	Nothing
The SeedLink pre-flight `UnitWeight` write, before 2026-08-23	false by construction	HTTP 200	Nothing: logged "updated", then "did not persist", every run on a production replica

Items belong to the facility that created them

How to mint an item without guessing a category

The item-creation cascade: what each step reads and what it guarantees
Step	What it reads	What it guarantees
Reuse	An existing `Each` item matching the strain and the size	No create at all; a re-run finds the same item
Same-size sibling	A same-size sibling item’s exact name and its real `ProductCategoryName`	The category is copied from a real item, never guessed; the name follows the sibling with the strain swapped
Learned template	The dominant "{strain} {size}" name skeleton in the brand’s own item history, with at least 2 items sharing it	A size the brand has never shipped gets a name in the brand’s own convention, and the brand’s most common flower `Each` category
Plain or bulk	No `Each` items at all, or no skeleton shared by 2 items	A plain "{strain} {size}" name, or the line ships as bulk grams

UnitWeightUnitOfMeasure is hardcoded to Grams on every create path. A unit-of-measure mismatch on that field multiplied a weight by 1,000 in one live test in June 2026, so the unit is pinned rather than passed through.
ItemCategory is always copied from a real sibling item or from the brand’s most common flower Each category, never inferred from a keyword, because it prints on the sticker.
Every create path finds by exact name first, so a retry reuses and never double-mints.
Auto-creation is scoped to flower with a known strain; concentrates carry a null StrainName and are reuse-only.

The unit weight is not the draw

Check it yourself: one read answers it, one write confirms it

The flag is readable with one GET and no writes. The confirmation needs a write, so do it on a sandbox item you own and send only the field you are testing, because the PUT is live.

GET https://api-ri.metrc.com/items/v2/categories?licenseNumber=<your license>
Authorization: Basic <base64 of VENDOR_KEY:USER_KEY>

for each row in the response:
  note Name and RequiresUnitWeight

then, for one item you own in a category whose flag is false:
  GET  /items/v2/<item id>                        record UnitWeight
  PUT  /items/v2/?licenseNumber=<your license>    the item, UnitWeight set, UnitWeightUnitOfMeasure "Grams"
  GET  /items/v2/<item id>                        compare UnitWeight to what you sent

If the read-back matches what you sent, the category keeps unit weights. If it comes back unchanged beside a 200, you have reproduced this page, and the value belongs on your side of the integration.

Questions

Is the dropped UnitWeight a Rhode Island sandbox bug?: No. The matrix was run on the sandbox on 2026-07-09, and a read-only pass over production packages in July 2026 agreed: the only weight-based production packages carrying a unit weight sat in Terpenes/Non Psychoactive Derivatives, the one concentrate category with RequiresUnitWeight true, and the weight was set at item creation.
Why does PUT /items/v2/ return 200 if it ignored my UnitWeight?: Because the call as a whole succeeded. The endpoint applies the fields the category allows and discards UnitWeight on a flag-false category; a Name change on the same call persisted. The body is {"Ids":[N],"Warnings":null} either way, so only a read-back shows the difference.
Which categories keep UnitWeight?: The ones whose row on GET /items/v2/categories carries RequiresUnitWeight: true. Of the 7 categories tested on 2026-07-09, 3 keep it (Shake/Trim, Infused Pre-Rolls, Pre-Packaged Bud) and 4 drop it (Bud/Flower, Kief, Concentrate, Concentrate (each)). Rhode Island served 21 categories on 2026-07-28; read the flag for the rest rather than inferring it from the name.
Can I make a bulk flower package sellable as fixed units by writing UnitWeight to METRC?: No. A package with a null unit weight is in a flag-false category by construction, and that is exactly where the write is dropped. Keep the per-unit weight on your own side and re-apply it after every sync, which is what SeedLink does; its packaging pre-flight has written nothing to METRC since 2026-08-23.
Why does my PUT fail with "Item N does not exist at the current Facility."?: Because the license on the call is not the facility that created the item. Items are facility-scoped: only the owner accepts PUT /items/v2/, and a non-owner answers HTTP 401, 404, or that 400. Read with GET /items/v2/{id}, which works across facilities, and write from the owning license.
What happens if UnitWeightUnitOfMeasure is not Grams?: A unit-of-measure mismatch on that field multiplied a unit weight by 1,000 in one live test in June 2026. SeedLink hardcodes the field to Grams on every create path rather than passing a unit through.
How do I create an item for a size I have never sold without guessing the category?: Copy it from a real item: reuse an existing Each item for the strain and size, else copy a same-size sibling’s exact name and ProductCategoryName, else render the brand’s own dominant name skeleton (at least 2 items must share it) at the new size with the most common flower Each category. On the sandbox in July 2026 this created a "<strain> - 7g" item at 7 Grams for a strain that had only 3.5 g items, and a re-run reused it.
Does the parent item’s UnitWeight matter when packaging?: Not in SeedLink’s packaging flow: nothing reads it, and every per-unit weight comes from SeedLink’s own row. What does matter is the source package’s unit of measure, read live from UnitOfMeasureName, because a draw in grams from an Each source is rejected by METRC.

Sources and how to cite this page

Live-tested matrix of PUT /items/v2/ and POST /items/v2 against the RequiresUnitWeight flag on GET /items/v2/categories, Rhode Island sandbox, one cultivator facility, 2026-07-09; the wrong-facility 400 body observed the same day.
Read-only read of weight-based active packages carrying a unit weight at Rhode Island production cultivator facilities, July 2026.
GET /items/v2/categories at one Rhode Island production cultivator facility, read live, 2026-07-28; the table is pinned by a test in the SeedLink repository, so the page cannot drift from the code.
SeedLink item-creation cascade and multi-pack item flow, live-verified on the Rhode Island sandbox, July 2026; the packaging pre-flight change of 2026-08-23; the unit-of-measure guard from a live test in June 2026.
SeedLink METRC field guide (docs/METRC.md), sections UnitWeight persists ONLY for RequiresUnitWeight=true categories, Items Are Facility-Scoped, Tier A Category-Aware UoM, and Categories.

Machine-readable copy of this page, with the same facts, dates and sources: /guides/metrc/unit-weight-requires-unit-weight/data.json

METRC item UnitWeight in Rhode Island: it persists only when the category has RequiresUnitWeight true, and the PUT returns 200 either way

What this page is

The flag lives on the categories endpoint, not on the item

The 200 is real, and it is not a sandbox bug

A null unit weight can never be repaired by writing it back

Items belong to the facility that created them

How to mint an item without guessing a category

The unit weight is not the draw

Check it yourself: one read answers it, one write confirms it

Questions

Sources and how to cite this page

Related

METRC item UnitWeight in Rhode Island: it persists only when the category has RequiresUnitWeight true, and the PUT returns 200 either way

What this page is

The flag lives on the categories endpoint, not on the item

The 200 is real, and it is not a sandbox bug

A null unit weight can never be repaired by writing it back

Items belong to the facility that created them

How to mint an item without guessing a category

The unit weight is not the draw

Check it yourself: one read answers it, one write confirms it

Questions

Sources and how to cite this page

Related