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

With no annotations, the description carries the full burden, and it does disclose the ranking basis (embedding similarity) and that results are most-similar-first. It omits failure behavior for an unknown slug, whether results can be empty, and any read-only/pagination context, so meaningful gaps remain.

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 tight sentences: the first front-loads what is returned and the ranking algorithm, the second gives the use case. No filler, no repetition of the tool name.

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 two-parameter, read-only lookup with no output schema, the description covers what is returned and in what order, which is the essential information. It could note emptiness or unknown-slug behavior, but nothing critical to invoking it correctly is 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 description coverage is 100% and both parameters are documented there, including the limit default and maximum of 5, so the baseline is 3. The description adds nothing about slug format or the significance of the limit cap beyond what the schema already states.

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 (posts) and mechanism (text-embedding similarity to a given post), plus result ordering. It implicitly distinguishes itself from search_posts by similarity-to-a-post rather than query matching, but never names a sibling, so it stops short of full differentiation.

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 to follow a thread of ideas from one post to the next" gives one concrete scenario, which is more than nothing. However, it offers no when-not guidance and does not tell the agent when to prefer search_posts or list_posts instead, leaving the routing decision to inference.

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