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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=false), so the description's added value is telling the agent what comes back: the contact plus metadata.enrichment. It does not cover not-found behavior or how enrichment is structured, which keeps it below 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?

Two sentences, no filler, with the return-content fact front-loaded and the usage condition immediately after. Every clause carries 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?

For a read-only, 2-parameter tool with no output schema, the description supplies the crucial return-value context (metadata.enrichment) and the reason to call it. Missing only edge-case behavior such as missing contacts or enrichment payload shape.

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 only 50% - contact_id is undocumented - but the description compensates by framing the call around enrichment and the schema explains include_enrichment's default and the false case. The description reinforces the enrichment semantics rather than repeating the schema verbatim.

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 ('Read a contact') plus a distinctive scope: it returns the agent's accumulated knowledge in metadata.enrichment, not just the raw row. This separates it in spirit from search_contacts and contacts_get_batch, though those siblings are never named explicitly.

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?

Gives explicit trigger conditions: call before answering questions about a person, or before judging whether a newly observed fact is novel. That is real when-to-use guidance. It stops short of naming alternatives (e.g. contacts_get_batch) or when-not conditions.

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