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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds real value by disclosing the returned fields (status, last run, item counts) and that collection scoping is optional, but says nothing about pagination, limits, or ordering. With annotations carrying the behavioral bar, a 3 is appropriate.

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 core content is one compact sentence that front-loads the returned fields and the optional filter. The trailing "Served by NicheDB (https://nichedb.dev/docs/mcp)" line is boilerplate that does not help an agent decide or invoke.

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 one optional parameter, no output schema, and full schema coverage, the description does enough to call the tool correctly. It is thin on how this listing relates to downstream tools (feed_items, get_item), which would help an agent chain calls.

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 the collection parameter already carries a description with an example slug and a pointer to list_collections. The description's "Optionally one collection" adds only the optionality framing, which the schema's non-required status already communicates, so this is baseline.

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 names the resource (sources) and the fields each entry carries, but it uses a noun phrase with no verb, leaving the agent to infer the list operation from the tool name. It does implicitly distinguish sources from siblings like list_collections or list_feeds, but differentiation is by resource noun only, not by stated action.

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 only usage signal is "Optionally one collection," which conveys scoping but not when to choose this tool over siblings such as feed_items or list_collections. There is no guidance on when to omit the collection filter or what to do with the results.

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