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

Annotations already declare readOnly, idempotent, non-destructive behavior, so the safety profile is fully covered. The description adds state-dependent detail (published posts carry published_at/published_url, failed or held publishes carry a one-line publish_error), but since an output schema exists, much of this describes return shape rather than behavior beyond structured data.

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 dense sentences, front-loaded with purpose and then expanding on return states and expansions. No filler, though the state-field enumeration partially duplicates what the output schema already provides.

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 getter with annotations and an output schema, the description covers purpose, expansion behavior, and state-dependent fields. The only gap is response_format (concise vs detailed), which is left entirely to the schema.

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, but the description adds real meaning to the include enum values — analytics yields performance data, history yields the state-machine attempt log. It does not mention response_format at all, leaving one parameter to the schema alone.

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?

Specific verb and resource ('Fetches a single post by id') with explicit scope ('single', id-based), which inherently separates it from list/search siblings like search_posts or list_accounts. An agent knows exactly what it gets.

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?

The description says when the include expansions are worth requesting (analytics for performance data, history for publishing-attempt history), which is genuine invocation guidance. It never states when to prefer this tool over search_posts or list-based retrieval, so tool-selection guidance is only implied.

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