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

Beyond the `readOnlyHint` annotation, the description discloses useful behavioral details: it returns a per-year histogram, defaults to oldest order, supports random ordering, and narrows by year or tag. This gives an agent meaningful information about what happens when the tool is invoked.

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?

The description is front-loaded with the core purpose and each sentence provides distinct value: scope, ordering options, usage rationale, and return shape. There is no filler or redundant restating of the title or schema.

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?

The description explains the return behavior (per-year histogram) and covers the key options and use case, which is adequate given the annotations and fully described schema. It could be slightly more explicit about whether the response also includes post lists alongside the histogram, but overall an agent has enough context to call the tool 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 coverage is 100%, so the baseline is 3. The description adds value by explaining that the tag parameter is alias-aware, that year restricts to a single year, and that the default `oldest` order corresponds to content other surfaces do not expose. The `limit` parameter is not explicitly discussed in the description, but the schema already documents it fully.

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 action and resource: 'Reach the DEEP catalogue — every post back to 1993'. It clearly distinguishes itself from other listing surfaces by emphasizing that it exposes the full archive rather than the recent date-descending feed.

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 explicitly says 'Use this when you want to know what is actually IN the archive' and explains why other listing surfaces are inadequate for that goal. However, it does not explicitly say when NOT to use it or name a specific alternative like `search_blog_posts`, so the guidance is clear but lacks an explicit exclusion.

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