get_agent_custom_css

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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive, so the safety profile is covered. The description adds real value beyond that by disclosing the return shape ('raw CSS string, empty string if none set'), which the agent cannot get anywhere else since no output schema exists.

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 with zero filler: what it reads, what it returns, and when to use it. The core purpose is front-loaded and the caller guidance closes the description.

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 single-parameter read tool, the description covers purpose, return value semantics (including the empty-string case, which prevents an agent from misreading an empty result as an error), and workflow placement relative to the update sibling. Nothing an agent needs to call it 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?

Schema description coverage is 100% and the single agentId parameter is documented there. The description does not add format, source, or constraint detail beyond 'the agent ID whose customCSS field you want to read', so it performs at the baseline where the schema does the heavy lifting.

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 (read the agent's customCSS field) and immediately clarifies what that field is (the per-agent CSS override applied to the chat widget). That parenthetical alone distinguishes it from generic agent reads like get_agent and from the write counterpart update_agent_custom_css.

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 says when to call it: 'Use this before editing so you can produce a merged result for update_agent_custom_css.' This names the alternative (the write sibling) and the sequencing condition that selects this tool, leaving nothing to inference.

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