Scan a tools/list export

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

Annotations already declare readOnlyHint, openWorldHint=false and idempotentHint, so the safety profile is covered; the description reinforces it with 'Nothing is started or contacted'. It adds genuine context beyond the annotations by noting that the servers form also checks shadowing between servers, which changes what the tool does depending on input shape.

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?

Two sentences, zero filler, with the input contract and the no-side-effects guarantee front-loaded before the return description. Every clause carries information an agent needs to choose and call the tool.

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?

An output schema exists and annotations cover safety, so the description does not need to explain return values, and it is appropriately sized for a three-parameter tool. Minor gaps remain around malformed-input behavior, but nothing required for correct invocation 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%, so baseline would be 3, but the description earns extra credit by enumerating the three concrete export shapes (tools object, bare array, servers map) where the schema only offers a generic anyOf of object/array. It also makes the fail_on behavior interpretable in context, though the name parameter goes unmentioned.

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 and resource ('Run every static mcp-guard rule over a tools/list result') plus the accepted input shapes, and the phrase 'you already have' implicitly separates it from the live-connection sibling scan_server. An agent can tell what it produces ('a Markdown report and the findings') without opening the 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?

Clearly scopes usage to an export the caller already possesses and adds 'Nothing is started or contacted', which tells the agent this is the offline path. The exclusion is implied rather than explicit — it never names scan_server as the alternative for live servers — so it falls short of a full when/when-not statement.

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