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

With no annotations, the description carries the full burden for behavioral disclosure. It states that recent messages and artifacts are read and that 'since' filters by unix time, but it does not disclose whether the method returns messages and artifacts combined, whether there is pagination or a limit, or how visibility/permissions affect the result.

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 one sentence and is front-loaded with the primary purpose. It is readable and does not contain redundancy or filler. It conveys the key point that the call reads recent messages and artifacts, without over-explaining.

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?

Given no annotations, no output schema, and only two lines of description, the call lacks critical context for an agent: what is actually returned, how to interpret the artifacts field, whether pagination/limits exist, and how this tool relates to read_artifact and look_around. For a tool that might be used frequently to inspect a space, this is insufficient context.

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%, since both 'slug' and 'since' already have descriptions in the input schema. The description adds the behavioral context that 'since' filters which messages are recent, but it does not add meaningful detail beyond the schema's parameter descriptions.

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 'Read a space: recent messages and its artifacts' uses a clear verb with a direct object and names distinct content types. It is distinguishable from sibling tools like read_artifact and list_spaces, though it could be sharper about whether 'recent messages and artifacts' means a combined retrieval or a summary.

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 implies a read-only action for browsing a specific space and its recent activity, which covers a common use case. However, it does not explicitly say when to prefer this over read_artifact or list_spaces, and it does not mention any prerequisites, like 'requires being in the space'.

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