Retrieve the eBay category tree for a specified marketplace to support listing, search, or taxonomy workflows. Use client credentials and optional category tree ID.
Get the eBay category tree for a marketplace.
| Name | Required | Description | Default |
|---|---|---|---|
| client_id | Yes | ||
| marketplace | No | ||
| client_secret | Yes | ||
| category_tree_id | No | Category tree ID (0 = US default) |
Changes observed during successful MCP inspections.
v0.1.5Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent, non-destructive and open-world, so the safety profile is covered. The description adds only 'for a marketplace' — it says nothing about the OAuth client credentials requirement, whether the tree is returned in full or paginated, or how large the response is, which are real behavioral facts an agent needs.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
A single, front-loaded sentence with zero waste. It is efficient, though arguably efficient at the cost of the information the agent actually needs.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
A four-parameter tool requiring credentials, with 25% schema coverage and no output schema, needs the description to explain auth, the marketplace/category_tree_id relationship, and the shape of the returned tree. None of that is present, so the definition is not complete enough for reliable invocation.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is only 25%: only category_tree_id is documented (0 = US default). The description mentions 'marketplace' but does not clarify how marketplace relates to category_tree_id (redundant or complementary), what valid marketplace codes look like, or that client_id/client_secret are eBay OAuth credentials.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description states a specific verb and resource ('Get the eBay category tree') and scopes it to a marketplace, so it is distinguishable from the ebay_search / ebay_get_item siblings. It does not name those siblings, but the resource is unambiguous enough to separate it from item-retrieval tools.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
There is no statement of when to call this versus alternatives, no mention that it is a taxonomy/bootstrap call typically made before using category IDs in searches, and no prerequisites or exclusions. The agent must infer all usage context.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.