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

With destructiveHint=true and openWorldHint=true already declared, the description still adds genuinely new context: the outbound email has an external recipient and the call blocks waiting for owner approval. It does not say what happens on rejection/timeout, or that repeated calls produce duplicate sends (relevant to idempotentHint=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?

Two short sentences, zero filler, with the core action first and the blocking-approval caveat second. Nothing to trim.

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?

A five-parameter mutation tool with full schema coverage and no output schema; the description covers delivery target and the approval gate. The main remaining gap is post-approval behavior — whether a failure surfaces as an error and whether the sent PDF is persisted — which an agent would want before relying on the result.

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% with sensible defaults for `to`, `subject`, and `copy_me`, so the schema carries the load. The description only echoes the `to` default behavior and adds no formatting, address-validation, or `message` semantics beyond what the schema states. Baseline 3 applies.

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: emails the estimate as a PDF. The resource name implicitly separates it from the sibling send_invoice and send_change_order tools, but it never explicitly contrasts them or mentions whether alternate delivery paths (e.g. create_share_link) exist.

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?

"To the customer or to the addresses you give" implies when the `to` override applies, but there is no explicit when-to-use vs. when-not guidance, no prerequisite that the estimate be finalized/approved, and no mention of what to do if the owner rejects.

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