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

Annotations already declare readOnlyHint and destructiveHint=false, so safety is covered. The description adds real behavioral context beyond that: onchain is null when the capture was never anchored, and a 202 deferred response when the registry is undeployed. It stops short of describing retry/polling behavior for the deferred case.

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?

Three compact sentences: what it looks up, what it returns, and the two edge-case behaviors. Front-loaded with the core purpose and no wasted words.

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 having no output schema, the description enumerates the return shape (registry address, captureHash, decoded anchor tuple fields) and the two special states (null onchain, 202 deferred). An agent has everything needed to call and interpret this 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 coverage is 100% and the single captureHash parameter is fully documented (hex, 0x-prefix, sha256: format, server-side bytes32 padding). The description only restates '32-byte captureHash', adding nothing the schema doesn't already say, 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?

States a specific verb (look up), resource (a capture's on-chain anchor record in CaptureClassRegistry), and key (32-byte captureHash). This clearly separates it from the write-side sibling pcc_capture_anchor and from status/upload tools.

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 implies this is the read path for an existing capture's anchor, but it never states when to prefer it over pcc_capture_status, pcc_capture_anchor, or pcc_get_request. No explicit exclusions or routing guidance is given.

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