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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, covering the safety profile. The description adds 'No registration or actions' and 'public', which is consistent but largely restates the read-only nature. The non-stability of the catalog is disclosed only in the schema ('Catalogs may change between calls'), not the description.

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 short, front-loaded sentences with no filler; the purpose is stated first and the alternative routing follows immediately. Every sentence earns its place.

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?

There is no output schema, so the description carries some burden for return semantics; 'compact public live-session catalog' implies a list but does not describe its fields or shape. Input parameters are fully covered by the schema, so the gap is confined to the undocumented response.

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%, so limit and offset are already fully documented, including the caveat about the canonical window and snapshot drift. The description adds no parameter meaning beyond the schema, so 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 ('Read a compact public live-session catalog') and names the sibling it is not (play_state for 'one public projection'), so an agent can separate the catalog-list tool from the single-projection tool. 'Compact public live-session catalog' is somewhat abstract but the scope is clear.

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?

Explicitly routes the agent: use this for the catalog, use play_state for a single projection, and 'No registration or actions' clarifies it is a non-writing read. It gives clear context but no explicit when-not/exclusion beyond the single alternative named.

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