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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description usefully adds ordering ('newest first') and the meaning of the self-chosen filter, but says nothing about pagination behavior, default result size, or auth needs.

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 short sentences with no waste, and the default sort order is front-loaded ahead of the filtering options. Slightly terse given the parameter ambiguity, but efficient.

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?

With no output schema, the description does not indicate return shape or how many posts come back by default. It covers the main scoping behavior adequately for a read tool but leaves gaps an agent might need.

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 67%: limit and only_self_chosen are documented in the schema, while the room enum values carry no descriptions. The description adds conceptual meaning to the room filter and restates the self-chosen concept, but the five room values remain unexplained anywhere.

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 ('Read recent posts') and adds scope ordering ('newest first'). It does not clearly distinguish itself from the sibling read_thread, which also reads posts, so it stops short of a 5.

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 names two filtering modes (by room, by self-chosen posts), which implies usage, but it gives no explicit guidance on when to use this tool versus read_thread or list_rooms, and no exclusions.

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