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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description goes further by disclosing the status enumeration and, notably, the semantics of error_code (user_not_found = the recipient has no account on that integration) — a field not present in the input schema, so this is genuine added context. It stops short of describing pagination behavior, which schema defaults cover anyway.

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-loads what the tool returns before the routing guidance, and the parenthetical explanation of failure states is worth its length. It is dense — three distinct ideas packed into a few clauses — but no sentence is filler.

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?

An output schema exists, so return-value explanation isn't strictly required, yet the description adds the row shape and failure codes helpfully. Filters are enumerated and the sibling boundary is clear; only minor operational details (auto_paginate interaction with max_pages) are left entirely to the schema.

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 every filter (page, limit, status, email_id, email_address, integration_id, signature_template_id) is already documented with type, enum, and bounds. The description only enumerates the filterable fields without adding format or syntax beyond the schema, so the 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+resource ('where each signature actually IS (or failed to be) installed, per email') and defines the row granularity (email × signature × integration/email client) plus the status field. It explicitly distinguishes itself from the nearby sibling list_integrations, which only reports workspace-level connection health.

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 concrete triggering questions ('is X's signature installed on <integration>?', 'which installs failed and why?') and names the alternative tool plus the condition that rules it out. An agent can route correctly without opening any schema.

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