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

With no annotations supplied, the description carries the full disclosure burden and does well: it declares read-only behavior, states 'Side effects: None', and specifies the exact miss payload { found: false, item: null }, which prevents an agent from misreading an empty result as an error. It does not mention authentication/visibility boundaries beyond the PUBLIC READ tag, nor any throttling.

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 short sentences with the access tag and verb front-loaded, followed by return contents and the miss case. Every sentence adds information and nothing is padded.

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?

For a two-parameter read with no output schema and no annotations, the description supplies the return fields and the not-found shape, which is the main thing an agent needs. The only real gap is the absence of guidance against the many vault_* and pi_hydrate siblings in this toolset.

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%, so both 'id' and 'client_hash' are already documented in the schema; the description repeats only the ID-centric framing and adds nothing about the 304-validation semantics of client_hash. Baseline 3 is appropriate when the schema does the heavy lifting.

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 ('Retrieve specific knowledge item by ID') and enumerates the payload ('complete metadata, type, and Pi Pointer'), which makes the by-ID lookup clearly distinct from a search-style sibling like vault_query. It stops short of naming any sibling explicitly, so the differentiation is implied rather than guaranteed.

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?

'Retrieve ... by ID' implies the usage condition (you already hold a canonical ID), and the '[PUBLIC READ]' tag signals the access context. However, there is no explicit when-to-use vs. when-not-to-use guidance and no routing toward vault_query or pi_hydrate for agents that only have partial information.

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