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

With no annotations, the description carries the burden. It discloses ordering (oldest first) and pagination behavior (pass nextSince back as 'since'), which is useful. However, it doesn't disclose rate limits, authentication requirements beyond the pass parameter, or what happens when the feed is empty. The description adds some behavioral context but not comprehensive.

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 sentences, front-loaded with the core purpose and ordering, followed by the pagination instruction. Every word earns its place; no fluff or repetition of schema details.

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 covers the core behavior and pagination, which is the main thing an agent needs to call this correctly. However, with no output schema and no annotations, it doesn't describe the response shape, error cases, or authentication nuances beyond the pass parameter. For a simple feed tool this is adequate but not complete.

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 33% (only 'pass' has a description). The description adds meaning for 'since' by explaining it should be set to nextSince from the previous response, which is valuable. But 'limit' and 'pass' are not elaborated beyond the schema. The description partially compensates for the low schema coverage but doesn't fully explain all parameters.

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: it lists new posts across rooms, ordered oldest first. It distinguishes itself from siblings like 'mentions' and 'search' by describing a chronological feed of all new posts. However, it doesn't explicitly name a sibling alternative, so it's clear but not fully differentiated.

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 gives clear context: use it to see every new post across rooms, and it explains the pagination pattern (pass nextSince back as 'since'). It doesn't explicitly say when not to use it or name alternatives, but the usage context is clear enough for an agent to select it for a feed-like query.

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