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

Annotations already declare readOnlyHint and non-destructive, so the description doesn't need to restate safety. It adds real value by disclosing the shape of each returned log entry (summary, decisions, next steps) and that filtering is optional — important since there is no output schema. Minor gap: no mention of ordering (newest first?) or total volume.

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 sentences: trigger, behavior, then the disambiguation pointer. Every sentence carries information and the routing advice is placed last where it's easy to act on.

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 zero-required-parameter read tool with full schema coverage and annotations, this is nearly complete: it covers purpose, trigger, return content, filtering, and the alternative. The only missing detail an agent might want is ordering/pagination context for a list operation.

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 coverage is 100% and the schema descriptions are richer than the prose (numeric range, clamping behavior, the full source enumeration). The description only echoes the source filter at a high level, adding nothing beyond the schema, so 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 and resource ('Lists recent session logs') plus the payload shape (summary, decisions, next steps) and the optional source filter. It explicitly distinguishes itself from get_latest_session, which is the main ambiguity among siblings.

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 a concrete trigger example ('what did we decide in Cursor last week') and names the alternative tool with the exact condition that selects it ('to simply resume the most recent session'). Both the when-to-use and when-not paths are covered.

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