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

Annotations already cover the safety profile (readOnly, non-destructive, closed-world), so the bar is lower; the description still adds real behavioral context: namespacing of downstream tools as `ext__<name>__<tool>`, the ability to invoke them directly to probe returns, and the fact that disabled servers are silently omitted from results. It stops short of describing result shape or pagination.

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 what the tool returns and what feeds need from it, followed by the namespacing tip and the exclusion note. Every sentence carries information; no filler.

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 must carry the return semantics — it does so at a high level (servers plus the id a feed needs) but not the exact fields. For a read-only, annotation-covered list tool with a single well-documented optional parameter, this is close to 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?

Only one parameter exists and the schema documents it fully (workspace slug, omit to use the pinned workspace). The description adds nothing about the workspace argument, so it sits at the baseline of 3 for a fully-covered single-parameter schema.

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 states a specific resource — connected servers exposed to this workspace, along with the id a feed requires — which is clearly distinct from sibling listers such as ledger_feeds_list or caliper_sources_list. The verb 'list' lives only in the title, so the action itself is inferred rather than stated, but the resource and its purpose (feeding a metric feed) are unambiguous.

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 gives a concrete workflow hook ('call one directly to see what it returns before proposing a feed'), which tells the agent when to reach for this tool relative to creating a feed. It also states a when-not case (servers the workspace has switched off are not listed and cannot be fed from here), though no sibling is named as an alternative.

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