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

With no annotations, the description carries the burden and does well: it discloses that retired entries remain listed, that there is no database read (registry compiled into the running Worker), the exact freshness windows (observed_at, valid_until, stale_if_error=86400, deployed_at null when unavailable), and that receipt signing is additive with failures never costing the observation. Auth requirements and rate limits are still unstated, so not a full 5.

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?

Purpose is front-loaded and the Freshness paragraph earns its place since there is no output schema to explain those fields. The opening citation 'Spec 097 FR-010 / ADR-034' is opaque internal jargon that consumes space without helping an agent decide or call.

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?

With no output schema, the description compensates by describing the returned entries and the freshness metadata, which is the essential return-value information. It omits access/permission requirements, which leaves a modest gap for an otherwise self-contained read 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?

Schema description coverage is 100% and the single receipt parameter is fully documented in the schema, so the baseline is 3. The description's 'Add ?receipt=true for a signed Receipt v1.0 over the same payload' mostly restates the schema, though it adds the signed-payload framing.

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 names a specific verb+resource: it 'Returns the tool registry generated from openapi.yaml', and enumerates the entry fields (version, status, lens, schema hash, registry_hash). It is unambiguous on its own, but it never contrasts itself against close siblings like get_freshness, health_check, or get_stats, so an agent must infer the boundary.

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?

There is no when-to-use / when-not-to-use guidance and no named alternative. The reader can infer the tool is for registry discovery, but nothing tells them when this is preferable to get_freshness or health_check, or what prerequisites exist.

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