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

The description goes well beyond the annotations' readOnlyHint and openWorldHint by disclosing concrete behaviors: 'Pure read: no live probe, no network, instant.' It also reveals return details (freshly signed attestation for offline verification, feed_size on miss, observation_count on hit) and clarifies the tool's role as measurement-only, not endorsement. These details are not present in the annotations and add significant transparency.

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?

Although front-loaded with the core purpose, the description is extremely verbose, containing long parentheticals and asides that obscure the message. Each sentence packs multiple clauses (e.g., the feed_size/observation_count note, the 'measurement only' disclaimer, and the offline verification detail). For a tool with a single parameter, this level of verbosity is excessive and likely burdens the agent's parsing. It would benefit from tighter, more structured writing.

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?

The description is exhaustive for a read-only lookup: it states what it retrieves, how to handle a miss, what the response contains (feed_size/observation_count), that the result is independently signed and verifiable offline, and that it is not a safety or trust verdict. Even without an output schema, the agent has all necessary context to call the tool and interpret results correctly. No important operational aspect 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?

The single parameter (url) has 100% schema description coverage, so the schema already explains what it expects (URL or domain). The description adds no additional parameter-level meaning beyond the schema; it only repeats the general scope. Per calibration, baseline for high coverage is 3, and the description does not offer extra parameter syntax or format details.

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 clearly states a specific verb ('Look up'), resource ('SaSame's EXISTING, independently ed25519-signed Readiness attestation'), and scope ('for any MCP/agent endpoint'). It explicitly distinguishes itself from related tools by clarifying it is measurement-only and not an endorsement, and it differentiates from siblings like readiness_report and verify_mcp_ready by focusing on independently signed attestations an agent cannot issue about itself. The purpose is unmistakable and free of ambiguity.

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 description gives clear context for when to use the tool: to retrieve an existing attestation, and provides a specific alternative (call audit_mcp) when the endpoint is not yet observed. It also states what the tool is NOT (a safety, quality, or trust verdict), which helps agents avoid misusing it. However, it does not explicitly compare against sibling tools like readiness_report or trust_compare, leaving some routing decisions to the agent.

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