Umbra open SAR archive

get_item

Read-only

Return the full context card for one item.

``url`` is the JSON URL of an open-data STAC sidecar, a GEC/SICD (or other
product) filename such as ``2025-05-17-17-43-46_UMBRA-08_GEC.tif``, or the
acquisition stem ``2025-05-17-17-43-46_UMBRA-08``. A filename or stem is
resolved through the local catalog index: the stem is matched against
asset hrefs, which is what distinguishes ``sar-data/tasks/``,
``sar-data/task-data/``, and ``open-data/`` — the name itself does not.
Zero matches is an error. More than one match lists the candidate STAC
URLs; pass one of those. The hosted server resolves a filename or stem
with the catalog index it already loaded. A local server does the same
after ``umbra index fetch``.

When the index contains a STAC URL, the indexed snapshot is returned —
the same document ``search_catalog`` already answered from — rather than
a live re-fetch that can disagree on asset filenames or product types.
When the server is configured with a token (``$UMBRA_CANOPY_TOKEN``) and
``url`` is a bare acquisition id (no ``://``, and not a filename or stem),
it is instead looked up in Umbra's authenticated commercial archive by a
keyed STAC search — the retrieval complement to ``search_catalog`` over
the paid catalog, since archive cards carry an ``id`` (not a fetchable
sidecar URL) as their hand-off pointer. A filename or stem still resolves
from the local open-data index when a token is set.

The card (:meth:`UmbraItem.to_llm_context`) carries the id, ISO datetime,
place, bbox, resolution, polarization *with the change-detection caveat*,
the per-product-type explanations and asset URLs, and the mandatory
attribution line — everything a model needs to reason about the scene.

Input Schema

Name	Required	Description	Default
`url`	Yes

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedOct 26, 2026

TDQS

A4.5/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

There is no contradiction with readOnlyHint=true. The description goes well beyond annotations: it discloses that zero matches is an error, multiple matches return candidate STAC URLs to re-pass, indexed snapshots are preferred over live re-fetch to avoid asset-name disagreement, and a token enables a commercial-archive lookup by keyed search.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Core purpose is front-loaded in one line before the resolution rules, and nearly every sentence adds operational information. It is nonetheless long and partially repetitive — the rule that filenames/stems still resolve from the local index when a token is set restates earlier resolution logic.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a one-parameter tool with an output schema, this is more than sufficient: it covers input forms, deployment differences, failure modes, and the retrieval-on-demand role relative to ``search_catalog``. The card contents are also summarized despite the output schema already existing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters5/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 0% and the single ``url`` parameter has no description at all in the schema, so the description carries the full burden — and it does, enumerating the three accepted forms, the resolution mechanism (stem matched against asset hrefs), the token-gated commercial path, and error/candidate behavior.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The opening sentence states a specific verb and resource: 'Return the full context card for one item.' The body distinguishes its retrieval semantics from ``search_catalog`` (indexed snapshot vs. live re-fetch) and from other catalog tools, though that differentiation is embedded in detail rather than stated crisply.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It explains exactly which inputs are accepted and how each resolves — sidecar JSON URL, product filename, acquisition stem, or bare acquisition id under a token — and notes the ``umbra index fetch`` prerequisite for local servers. It is called 'the retrieval complement to ``search_catalog``', which implies the follow-up use case, but never states an explicit 'use this after a catalog hit / do not use for searching' rule.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

All Umbra open SAR archive tools Inspect

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