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NASA-PDS

NASA PDS Registry MCP Server

Official
by NASA-PDS

Crawl Context Product

crawl_context_product

Crawls a single PDS Context product to return its associated Context products—like targets and instruments—for NASA PDS Registry relationship mapping.

Instructions

Crawl a single PDS Context product and return other PDS Context products it is associated with. Ex. Mars 2020: Perseverance Rover (Investigation) is associated with Mars (Target) and Mastcam (Instrument), so it returns Mars and Mastcam.

WARNING: Takes a long time to run and performs several sequential API calls. Use wisely.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
urnYes

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv0.2.0

TDQS

A3.8/5.0
Behavior4/5

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

With no annotations, the description must carry the behavioral burden, and it does disclose the most consequential trait: long runtime and several sequential API calls. It also implies a read (it 'returns' associated products). It stops short of stating auth requirements, failure behavior, or result size limits.

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?

Front-loaded with the verb and resource, followed by a compact illustrative example and a warning. Three sentences, each carrying information; the example is slightly verbose but justifies its length by clarifying the associative return.

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

Completeness4/5

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

There is no output schema or annotation, yet the description conveys what is returned (associated products) and the cost profile, which is sufficient for a single-parameter tool. The URN input itself remains unexplained, which is the main incompleteness.

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

Parameters2/5

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

Schema description coverage is 0% and there is one parameter, 'urn'. The description never explains what a URN is, its format, or where to obtain one, only naming PDS product types (Investigation/Target/Instrument) inside an example. Since coverage is low, the description should have compensated and largely does not.

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

Purpose5/5

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

States a specific verb (crawl) and resource (a single PDS Context product) plus what is returned (other associated products). The Mars 2020 example makes the operation concrete and clearly separates it from the search_* and get_product siblings.

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

Usage Guidelines3/5

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

The WARNING ('takes a long time... use wisely') implies this is an expensive operation to invoke sparingly, which is contextual guidance. However, it never says when to prefer this over get_product or the search_* tools, nor does it give a precondition for choosing this tool.

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