Fetch metadata for a single OLS ontology by ID, including term count, version, homepage, and preferred prefix. Use for ontology lookup in annotation workflows.
Fetch metadata for a single OLS ontology (term count, version, homepage, preferred prefix).
| Name | Required | Description | Default |
|---|---|---|---|
| ontology_id | Yes | Ontology identifier, e.g. 'envo', 'go', 'chebi'. Case-insensitive. |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full behavioral burden. 'Fetch' implies a read-only lookup, and the listed metadata fields clarify the return content, but there is no mention of error behavior, authentication, rate limits, or what happens if the ontology does not exist. The description adds basic context but not complete behavioral transparency.
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?
The description is a single, front-loaded sentence with no wasted words. It states the operation, scope, and returned fields efficiently. Every part of the sentence earns its place.
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?
The tool is simple, requires one well-described parameter, and has no output schema. The description compensates by enumerating the metadata fields returned, which is the main missing context. It could say more about failure behavior or being read-only, but for this low-complexity lookup it is nearly complete.
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 description coverage is 100%, and the ontology_id parameter is documented with examples and a case-insensitivity note. The description adds no parameter meaning beyond the schema, so the baseline score of 3 is appropriate.
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 uses a specific verb, 'Fetch', and a precise resource, 'metadata for a single OLS ontology'. It also lists the returned metadata fields, making clear this is not a term-search or list operation. The word 'single' distinguishes it from the sibling mesa_ols_list_ontologies.
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?
The description implies usage: fetch this when you need metadata for one ontology. However, it does not explicitly state when to choose this over alternatives such as mesa_ols_list_ontologies or mesa_ols_get_term. No when-not or prerequisite guidance is provided.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.