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

With no annotations, the description carries the full burden and does well: it discloses credit consumption (none), demo-key behavior, the automatic follow rule (top five over 180 days, source 'fetch'), the 25-entry explicit cap, and that muted shows are handled separately. It omits return shape and ordering details, which keeps it short of a 5.

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?

Front-loaded with the core purpose, then progressively adds behavioral detail in four short sentences with no filler. The final credit/demo sentence is justifiable operational context, though it slightly dilutes focus at the end.

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 zero-parameter read tool with no annotations and no output schema, the description covers behavior, limits, credit cost, and sibling routing adequately. A brief hint at the returned structure (fields, ordering) would make it fully self-sufficient.

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?

The tool takes zero parameters, so the baseline is 4. The description's mention of source values ('fetch' vs 'explicit') is output-side context rather than parameter guidance, and nothing here misleads about inputs.

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 opening sentence names a specific resource ('The shows this key is kept current on') with an implicit list verb, and the description goes on to explain exactly what membership in that list means. It routes the agent to follow_podcast for adding entries and to list_new_episodes for episode data, so it is distinguishable from siblings without opening their schemas.

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?

It explicitly points to list_new_episodes for 'what is new' and mentions follow_podcast as the way to declare additional follows, giving clear context for when each alternative applies. It stops short of stating when NOT to use list_following (e.g. for muted-only or unfollow workflows), so it is not a full when/when-not treatment.

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