fetch_feedFetch and normalize any RSS / Atom / RDF feed by URL. CF-robust: fetches directly and falls back to a proxy if the source blocks the gateway. Use list_feeds first for curated sources.
| Name | Required | Description | Default |
|---|---|---|---|
| url | Yes | Feed URL, e.g. "https://news.ycombinator.com/rss". | |
| limit | No | Max items (1-50, default 20). | |
| query | No | Keyword filter over item title/summary. |
Changes observed during successful MCP inspections.
Input schema / examplesPrevious value: -[
- {
- "url": "https://example.com/feed.xml"
- },
- {
- "limit": 25,
- "query": "wind turbines",
- "url": "https://example.com/energy-feed.rss"
- }
-]New value: +[
+ {
+ "url": "https://phys.org/rss-feed/earth-news/environment/"
+ }
+]Input schema / examplesAdded value: +[
+ {
+ "url": "https://example.com/feed.xml"
+ },
+ {
+ "limit": 25,
+ "query": "wind turbines",
+ "url": "https://example.com/energy-feed.rss"
+ }
+]Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover read-only, idempotent and open-world traits, so the description adds genuine value with the CF-robust detail: a direct fetch that falls back to a proxy if the source blocks the gateway. It also notes normalization of heterogeneous feed formats. It does not describe the returned item shape, but that is largely schema's job given no output schema exists.
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?
Two sentences, zero filler. The core capability is front-loaded, followed by the operational resilience note and the routing hint.
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?
For a single-URL fetch tool with complete parameter documentation and full annotation coverage, this is nearly sufficient. The remaining gap is the return shape (normalized item fields), which an agent must infer since no output schema exists.
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 100%, so the url, limit and query parameters are already fully documented in the schema. The description reinforces the URL-centric entry point but adds no syntax or format detail beyond what the schema provides, so baseline 3 applies.
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?
States a specific verb and resource: fetch and normalize RSS/Atom/RDF feeds by URL. It distinguishes itself from list_feeds but leaves the sibling read_feed unaddressed, which is the more likely point of confusion.
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?
'Use list_feeds first for curated sources' gives one explicit alternative, and 'by URL' implies the trigger condition. However, there is no guidance on when to use fetch_feed vs. read_feed, and no exclusion criteria are stated.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.