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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds only the word 'public', which mildly implies no authentication is needed, but says nothing about rate limits, error behavior for unknown users, or freshness of the data. Modest added value above the annotations.

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?

A single terse noun phrase that front-loads the resource and lists the return fields with no filler. It is a fragment rather than a sentence, but every word earns 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 output schema, the description usefully enumerates the returned fields, compensating for the missing schema. It is nearly sufficient for a one-optional-parameter read tool, though it omits any error/not-found behavior.

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% for the single username parameter, so the schema already documents it fully. The description does not mention the username input at all, adding no semantics beyond the schema. 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?

The description names the exact resource (a Chess.com player's public profile) and enumerates the data it returns (name, country, join date, league, followers), which implicitly separates it from get_ratings and recent_games. There is no explicit verb or sibling callout, but the resource is unambiguous.

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?

There is no statement of when to use this tool versus get_ratings, month_summary, or recent_games, and no prerequisites or exclusions. The agent must infer usage purely from the resource name.

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

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds the useful behavioral fact that records are lifetime (not windowed) and covers four named time controls, but says nothing about auth requirements, rate limits, or behavior when no username is supplied.

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?

One sentence, front-loaded with the payload ('current and best rating'), with the enumerated time controls serving as a compact scope statement. No filler.

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 simple one-parameter read tool with no output schema, the description effectively documents the return shape by listing the data categories. The only shortfall is the undefined behavior of the optional username argument.

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 single username parameter is fully documented there, so the schema does the heavy lifting. The description adds no information about the parameter — notably it never explains what happens when the optional username is omitted, which is the one semantic 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 names a specific resource (ratings) and enumerates exactly what is returned: current and best rating plus lifetime win/loss/draw per time control. That content profile implicitly separates it from siblings like recent_games and month_summary, though no sibling is named explicitly.

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 by the data scope — an agent can infer this is the tool for a rating/record snapshot, but there is no statement of when to prefer it over get_profile or month_summary, and no exclusions or prerequisites.

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

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds genuine value by enumerating the derived metrics returned (rating change per time control, how wins/losses ended, best win, worst loss), which functions as an output contract in the absence of an output schema. No auth or rate-limit notes, but none are critical here.

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?

Front-loaded with the deliverable, then the default, then the usage cue; no filler sentences. The long enumeration of returned fields is dense but earns its place because no output schema exists.

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 output schema, the description correctly compensates by listing what comes back, and it covers defaulting behavior for year/month. It leaves one gap: username is listed as optional by the schema, yet the description never explains what happens if it is omitted.

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%, so year, month, rated_only, time_class and username are all documented in the schema itself. The description only echoes the current-month default, adding nothing beyond what the schema already states. 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?

The description states a concrete deliverable — a per-calendar-month performance summary — and enumerates its contents (record, rating change per time control, accuracy, streaks, openings). It is clearly differentiated from get_profile and get_ratings by the monthly aggregation, though it never names a sibling to contrast against.

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?

"Use this for questions like 'how did I do this month?'" gives an explicit trigger context, and "Defaults to the current month" clarifies the defaulting behavior. It stops short of stating when to prefer recent_games or get_ratings instead, so no exclusion guidance is present.

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

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description still adds real behavioral context beyond that: results are restricted to finished games (not in-progress), ordered newest first, and include result, ratings, opening, accuracy and a link. Missing only pagination/cap behavior and the fact that limit is capped at 50.

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?

A single front-loaded sentence that names the resource first and then the ordering and returned fields. No filler, no redundancy with the title.

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 read-only list tool with full schema coverage and annotations covering the safety profile, the description is nearly sufficient, and it partly compensates for the absent output schema by naming returned fields. It falls short only on the 'recent' semantics and the 50-item ceiling.

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%, so all three parameters (limit, username, time_class) are already documented with defaults and enum values. The description mentions 'a player's' only obliquely and adds no format or syntax detail beyond the schema, so the baseline of 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 resource (a player's most recent finished games) plus scope detail (newest first, finished only) and enumerates the payload fields. An agent can tell this apart from get_ratings or month_summary by resource alone, though no sibling is named explicitly.

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?

There is no when-to-use guidance, no mention of prerequisites (e.g. requires a valid Chess.com username), and no routing to or away from siblings like month_summary for aggregate views. It simply describes what the output contains.

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