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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the safety profile is covered. The description adds genuine conceptual context beyond that: templates are parent rows spawned by a daily cron, and the instances_generated counter reflects running output. It does not mention pagination or sorting, which is a minor gap for a list endpoint.

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?

Three short sentences plus a compact Returns block. The core purpose is front-loaded in the first sentence, and the remaining content is the disambiguation and return shape, each earning its place.

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?

With no parameters and no output schema, the description carries the whole burden and does so: it names the return envelope (templates, total_count) and the per-template fields, and explains the parent/child relationship. Nothing essential for calling this tool correctly is missing.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate at the parameter level; baseline for a 0-param tool is 4. No misleading parameter claims are made.

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 ('List the user's recurring transaction templates') and immediately disambiguates from the far larger sibling list_transactions by explaining that spawned children appear there, not here. An agent can distinguish this from list_transactions without opening either schema.

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?

Clearly indicates the context in which this tool is correct (retrieving parent templates) and where the spawned children live instead, which routes the agent away from the wrong listing. It stops short of explicit when-not-to-use guidance or naming alternative tools (e.g. list_transactions, get_subscription_status) directly.

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