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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuinely useful scope context — that only tallies are exposed and individual calls are withheld — which prevents the agent from expecting per-call records. It says nothing about refresh cadence, coverage window, or whether counts are final versus provisional, so it is solid but not rich.

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 sentences, no filler. The contents are front-loaded and the limiting clause ('counts only') comes last where it acts as a caveat rather than burying the payload. Every clause carries information.

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 must convey the return shape, and it does by enumerating the tallies. For a simple parameterless read tool this is close to sufficient; a note on how current the tallies are would make it fully self-contained.

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 and the schema is an empty object with additionalProperties false, so there is nothing for the description to explain. Baseline 4 applies: no parameter semantics are required.

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?

Names a specific resource (prediction ledger tallies) and enumerates exactly what it contains: open and graded call counts, next grading date, calls by side. A verb is absent but the read-only aggregate nature is unambiguous. It does not name a sibling like tc_get_report or tc_status to sharpen the boundary, so it stops short of a 5.

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?

Usage is only implied: an agent infers this is the tool for aggregate counts rather than per-call data. 'Counts only; individual calls are not published' usefully closes one path, but there is no explicit when-to-use statement and no named alternative among the sixteen siblings that also serve reporting-style data.

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