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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description goes beyond that by disclosing the return shape (id, address, target accounts, autoPublish flag, last read error) and the autoPublish semantics, which is meaningful context not present in structured fields.

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 sentences, front-loaded with the resource and behavior, then the return fields, then the routing guidance. Slightly dense with parentheticals, but each sentence carries distinct load and nothing is wasted.

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 and no parameters, the description must explain what comes back — and it does, listing every returned field and its meaning. Combined with the sibling-routing guidance, an agent has everything needed to call this correctly.

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. There is nothing to disambiguate and the description correctly omits parameter detail rather than inventing any.

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 ('Lists') and resource ('RSS or Atom feeds Broadcast follows'), and further clarifies the causal model — each new article becomes a post for the feed's accounts. An agent can distinguish this from follow_feed/unfollow_feed/update_feed without opening any schema.

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 names the downstream consumers and conditions: 'Call it to get the id that update_feed and unfollow_feed take, or before follow_feed to avoid following the same feed twice.' This states both when to call it and the concrete alternatives it feeds into.

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