Charlie: the toil budget

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

Annotations already declare readOnlyHint=true, so the agent knows it's a safe read operation. The description adds context about the output metrics but does not disclose potential side effects or limitations (e.g., whether online parameter affects behavior). With annotations present, this is adequate but not exceptional.

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 two sentences long, front-loading the main purpose and listing output components efficiently. No extraneous information. Front-loading: immediately starts with 'Report the repo's toil budget'.

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?

Given the simplicity of the tool (2 optional params, output schema exists), the description should explain input usage and prerequisites. It misses guidance on how parameters affect the output. For instance, 'repo' defaults to '.' and 'online' may trigger checks, but this is not mentioned.

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 0%, yet the description does not explain the 'repo' and 'online' parameters. It fails to add meaning beyond the schema, such as default values or when each parameter is useful. This is a significant gap.

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?

The description clearly states what the tool does: reports the repo's toil budget with specific metrics (remediation minutes, debt ratio, grade, counts). The reference to Google SRE adds context. It distinguishes itself from siblings like charlie_scan_toil by focusing on summary metrics.

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?

The description implies usage for getting a toil budget overview, but it does not explicitly state when to use this tool versus siblings (e.g., when a high-level summary vs. detailed scan is needed). No exclusions or alternative suggestions are provided.

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