Read your home timeline

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

Annotations already declare readOnly, idempotent, and non-destructive, so the safety profile is covered. The description adds genuinely useful non-annotation context: newest-first ordering and the authentication requirement ('Requires a connected account'). It does not mention pagination limits or rate limiting, but the essential behavior is disclosed.

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?

Three short sentences, zero filler, with the identity of the feed and the ordering front-loaded before the parameter hint. Every sentence carries information.

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 read-only tool with full annotations and complete schema documentation, the description covers what it returns (following feed, newest first), how to scope it, and the auth prerequisite. The absence of an output schema is not a problem since the return shape is obvious, but cursor/pagination behavior is left entirely to the schema.

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 the baseline is 3. The description explains the since_hours/limit tradeoff at a high level, but the schema already documents that tradeoff in more detail ('Instead of a fixed count... up to `limit`'), so the description adds little beyond the structured fields.

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 resource ('Your following feed') and an ordering guarantee ('newest first'), which distinguishes it from author/list feeds. It never names a sibling such as get_feed or get_author_feed, so the agent must infer which feed tool is the home timeline from the phrase alone.

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?

'Pass since_hours to read a time window rather than a fixed number of posts' gives clear guidance on parameter selection and 'Requires a connected account' states a prerequisite. However, it offers no guidance on when to choose this tool over get_feed, get_list_posts, or get_author_feed, which are all feed-reading siblings.

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