List standing sources

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

Annotations already declare readOnly/idempotent/non-destructive, but the description adds genuinely new behavior: results come as a keyset page from local storage, the cursor must be passed unchanged, and no poll or capture is triggered. That last clause rules out asynchronous side effects that readOnlyHint alone wouldn't make obvious. It stops short of noting data freshness or whether archived rows count against the page.

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 what is listed, then routing, then pagination behavior, in three tight sentences with no filler. Every clause carries information an agent needs.

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 5-param read tool with no output schema, the description covers the returned fields, the pagination contract, and the absence of side effects. Combined with full schema coverage and annotations, nothing needed to invoke it correctly is missing.

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 coverage is 100% and every parameter already has a description, so the baseline applies. The description reinforces cursor semantics ('pass its cursor unchanged to continue') but adds nothing about kind selection or the consent_state tradeoff beyond what the schema states.

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 (list) plus the exact resource (standing RSS, YouTube channel and playlist sources) and enumerates what each row carries: consent, enrollment, daily allowance, detection health. It also explicitly separates itself from source_status and the legacy list_podcast_feeds/list_monitored_playlists siblings, so an agent can pick correctly without opening 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?

Gives an explicit use case (find source_id values, compare source states) and names the alternative tools with the conditions that select them (source_status for a single source's observations, the legacy listers for feed/playlist IDs). Both when-to-use and when-to-use-something-else are covered.

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