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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds useful context beyond that: result ordering (newest first) and the shape of each returned item. It says nothing about result volume, pagination, or what happens with the limit cap, which the schema handles only partially.

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 tight sentences with zero filler: what it returns first, when to use it second, what to call next third. The ordering and returned-field detail is front-loaded before the usage guidance.

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 simple read-only list tool with full annotation coverage and a one-parameter schema, the description supplies everything needed to invoke it correctly, including the fields returned despite there being no output schema. The only gap is that it does not clarify its boundary against search_essays for theme-based requests.

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?

There is a single optional parameter with 100% schema description coverage, so the baseline is 3. The description's "every published essay" implies the default of returning all, but it adds no format or usage detail about the limit parameter beyond what the schema 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?

The description states a specific verb and resource ("List every published essay by Niels Langereis"), plus ordering ("newest first") and the fields returned (id, date, summary, links), so an agent knows exactly what it gets. It differentiates from get_essay ("for the full text") but never addresses search_essays, which is the closest sibling for thematic queries.

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?

It gives concrete triggers — browsing before choosing an essay, requests for his essays, his latest piece, or everything on a theme — and an explicit follow-up step ("Follow up with get_essay for the full text"). It lacks any when-not guidance, and the "everything on a theme" case overlaps with the search_essays sibling, which could route an agent to the wrong tool.

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