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

Discloses key behaviors beyond annotations: the operation is slow (60-120s with scrape+OCR+DNA+classify), idempotent on success, uses a 24h scrape cache, and refuses already-owned handles. This reinforces and expands on the idempotentHint=true annotation without contradicting readOnlyHint=false or destructiveHint=false.

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?

The description is dense but every sentence earns its place: purpose, uniqueness, timeout behavior, idempotency, and next steps. It is front-loaded with the core action and ends with practical follow-up routing, with minimal fluff.

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 complex mutation-like tool with no output schema, it covers creation semantics, exclusivity, failure/timeout behavior, and next steps well. The only notable gap is that it never states the structure or contents of the return value, but the idempotency and follow-up guidance partially compensate for that.

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 schema already documents all three parameters. The description adds context around idempotency and post-conditions but does not add parameter-level meaning beyond what the schema provides, so the baseline of 3 is appropriate.

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?

Purpose is explicit: 'Create and link a NEW pith.day account from a public Instagram handle', with concrete steps (scrape, derive Brand DNA, classify flow, seed drafts). It distinguishes itself from siblings by stating it is 'the ONLY tool that links a tenant to your user (MCP-17)'.

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?

Provides clear when-to-use guidance: only this tool links a tenant to the user, handles already owned by another account are refused, and it is safe to call again on timeout. It also names follow-up tools (get_tenant, curate_images, get_flow/set_flow), which is actionable routing advice.

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