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

Annotations already declare readOnly=false, destructive=false, idempotent=true; the description adds real value beyond them: cost (FREE/no credits), the fact it is a mutation, the new-record default status, and the white-hat guarantee that contact fields are manually entered rather than scraped. Idempotency is not restated, but there is no contradiction.

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?

Dense but well front-loaded: purpose first, then cost/safety, then scope note, then routing. Every clause carries information, though the 'Link Building Tool:' prefix is slightly redundant with the tool name.

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 9-parameter mutation with no output schema, the description covers cost, mutation status, white-hat constraints, default state, and next-step routing. Remaining gaps (label, targetUrl usage) are minor relative to what the schema already explains.

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 56%, and the schema documents projectId, domain, url, note, and targetUrl. The description adds a genuine constraint on the contact* fields (plain typed free text, never auto-scraped), but says nothing about label or targetUrl semantics, so it only partially compensates for the coverage gap.

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?

Opens with a specific verb+resource+scope: 'add one prospect domain/page to a project's list.' This is clearly distinguishable from siblings like update_link_prospect, add_link_prospect_note, and import_link_prospects_csv.

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?

Explicitly names the follow-up tool (update_link_prospect_status) and the lifecycle starting point ('prospected'), so an agent knows this is the entry step. It does not, however, contrast with import_link_prospects_csv for bulk adds or with add_link_prospect_note for appending activity.

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