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

Annotations already establish readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description goes beyond them by disclosing that raw payloads are redacted for contact fields, that they are stored/retrievable for field-by-field verification, and that includeRaw output is 'Large.' It does not cover failure modes (unknown canonicalId) or output volume expectations in detail, so it stops short of a 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?

Front-loaded with 'USE WHEN' and 'NEXT' signposts that make it scannable, with no filler sentences. It is somewhat dense and runs long for a 2-parameter read tool, but every clause carries routing or behavioral information.

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?

There is no output schema, so the description must describe returns, and it does so concretely (normalized fields plus per-source registry, source id, source URL, timestamp, checksum). With a simple 2-param schema and annotations already covering readonly/open-world status, nothing an agent needs to call this 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%, so the 3 baseline applies, and the description earns above it: for includeRaw it adds that the payload is the untouched registry record, that it has been contact-field redacted, and that it is the strongest evidence for verifying a specific claim field-by-field. canonicalId semantics (format examples) are left to the schema, which is acceptable.

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 and resource ('need the COMPLETE record: all normalized fields plus every source record behind it') and enumerates the returned fields (registry, source id, source URL, retrieval timestamp, payload checksum). It clearly distinguishes itself from the list-style siblings search_world_trials and find_trial_registrations by scoping to a single canonicalId.

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?

Begins with an explicit precondition ('USE WHEN you already have a canonicalId (from search_world_trials or find_trial_registrations)') that routes the agent from the search tools to this one. It also names follow-on alternatives with their purposes (find_trial_registrations for duplicate registrations, get_registry_sources for licence/sync state), so when-to-use and when-to-use-something-else are both covered.

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