fetch_feed

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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description still adds real value beyond that: it discloses the return shape {count, has_next_page, view_options, posts}, the cursor contract, and several non-obvious defaults (only_with_image=true, limit=21).

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?

One dense but front-loaded block: purpose first, then required parameter, then optional parameters, then return shape. For ten parameters this is compact, though the run-on parameter list is harder to scan than a short list would be.

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?

With no output schema, the description correctly compensates by naming the top-level response keys and the pagination field, and it covers the required tag plus every optional flag. An agent has enough to call and page through this correctly.

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%, so every parameter is already documented in the schema and the baseline is 3. The description largely restates those defaults and only adds the Cursor mechanics, which the schema also carries.

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 the post feed for a tag') and adds domain scope ('the homepage + category pages'), so an agent immediately knows this is category-browsing rather than a keyword query. It never names or contrasts a sibling such as 'search' or 'promoted_posts', which is the only thing keeping it from a 5.

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?

Usage is implied rather than stated: the tag-based framing and the pagination hint ('pass the last item's updateDate to get the next page') tell an agent how to page, but not when to choose this over 'search' or 'promoted_posts'. No exclusions or prerequisites are given.

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