List server tools

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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the redundant "Read-only" adds nothing. What does add value is the disclosure of result shape ("a line per tool, else per server with any error") and the note that an unreachable server is reported rather than silently dropped, which annotations cannot express.

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?

Four short sentences, each carrying a distinct fact (what, fallback alternative, safety, return shape), with the purpose front-loaded. The telegram style ("No server is reachable yet; this says why") is slightly cryptic and costs a point on readability.

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 single-parameter read-only listing tool with full annotation coverage and no output schema, the description supplies purpose, alternative routing, and return format. Only minor gaps remain, such as what happens with pagination on large catalogues and how it relates to describe_tool.

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?

There is one optional parameter with 100% schema description coverage, so the schema already documents `server` as a catalogue name to omit for all. The description's mention of per-server error lines slightly reinforces that scoping but adds no syntax or format detail. Baseline 3 is correct when the schema does the work.

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 concrete verb and resource ("List the tools on the connected MCP servers") and explicitly routes keyword-based lookups to search_capabilities, which separates it from that sibling. It does not explicitly contrast with describe_tool, so the differentiation is incomplete but still clear.

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?

"With a keyword, search_capabilities is cheaper" gives an explicit alternative plus the condition that selects it, which is exactly the routing guidance an agent needs. There is no statement of when-not-to-use beyond that single case, so it stops short of a 5.

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