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

readOnlyHint already covers safety, and the description adds substantial context beyond it: it reads a synced archive, syncs daily only for accounts that granted bookmark access, and a reconnect may be needed if nothing is synced. Ordering (newest first) and the author_counts rollup scope (ALL bookmarks) are also 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?

Single dense paragraph, front-loaded with the resource and ordering, then filters, then the sync/troubleshooting caveat. Information-dense and mostly waste-free, though somewhat packed into one block.

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 carries the return-shape burden by listing the fields returned and the author_counts rollup. It also covers the key operational caveat (un-synced account/reconnect), leaving nothing essential missing.

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% with all three parameters documented, so the description's notes on `query` (filters bookmark text) and `author` (one @handle) largely restate the schema. Baseline 3 is appropriate since the schema carries the parameter burden.

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+resource ('the posts the user bookmarked on X') and enumerates the returned fields (author @handle/avatar, text, date, engagement, link, author_counts). This clearly distinguishes it from siblings like get_my_tweets (own posts) and search_tweets (public search).

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?

Gives concrete usage context: use author_counts directly for 'whose posts do I bookmark most?' and use `author` to narrow to one @handle. It stops short of explicitly naming the alternative tools an agent might confuse it with, so it is clear but not fully routing-aware.

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