agentscan: check a remote MCP server (live?, name, version, sign-in, tools, latency, TLS)

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

Annotations already mark this read-only, idempotent, non-destructive and open-world, but the description goes well beyond them: one probe from Tanod's servers, no credentials, 15 s cap, 0.5-3 s typical, unresponsive server still charged, private/malformed address returns 422 uncharged, pricing and daily free quota, plus a prompt-injection warning about returned text.

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?

Information is front-loaded with the core purpose and alternatives first, then operational details. It is long and slightly repeats the title's field list, but nearly every clause (timeouts, charging, untrusted-data warning) carries decision-relevant content.

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?

Despite an output schema existing, the description still tells the agent what the probe returns, how long it takes, what errors mean, what it costs, and what safety caveats apply to the returned data. Nothing an agent needs to call this tool 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 description coverage is 100% and the single `url` property is already fully documented with format constraints (host name only, port 443, no user info). The description restates the same constraint ('the public https URL of the MCP server endpoint') without adding syntax or format details, so the baseline 3 applies.

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 verb and resource ('Check whether a remote MCP server is up and what it offers') and enumerates the concrete outputs (name, version, protocol, sign-in, tool count, latency, TLS expiry, status class). It also distinguishes itself from the two nearest siblings by naming scan_agent_package and preflight_mcp_listing directly.

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?

Explicit routing guidance is given: 'It reads no code; to scan a package before installing use scan_agent_package; to check a repo against an awesome list use preflight_mcp_listing.' Constraints (public https, port 443, no credentials, no redirects) and the charged-vs-not rules further disambiguate when this tool should be used.

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