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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and a closed world, so the safety profile is fully covered. The description adds one real nuance — only 'live' facts are returned, implying deleted facts are filtered out — but the rest of the sentence restates return fields that the output schema already provides.

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, front-loaded with the purpose and followed by the workflow instruction. The clause enumerating returned fields is marginally redundant given an output schema exists, but the text is still compact and every sentence carries weight.

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 one-optional-parameter read tool with a rich annotation set and an output schema, the description covers purpose, trigger condition, and the downstream {{fact:name}} pattern. Nothing an agent needs in order to call 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 the single blog_id parameter is already fully explained in the schema (defaults to the API key's blog, must match, required without keys). The description adds nothing about parameters, so the baseline 3 applies.

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 and resource ('List the blog's live facts') and enumerates what each fact carries (value, when it was confirmed/changed, posts that use it). It is clearly the read counterpart to set_fact/delete_fact, though it never names a sibling explicitly.

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 when-to-use direction: 'Check here before writing a price, version, limit or count,' plus the follow-up action ('use {{fact:name}}'). No explicit when-not-to-use or named alternative (e.g. set_fact for creating), so it stops short of a 5.

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